Eric Settle Presents Rifle Reloading Information

BASIC RULES FOR RELOADING SAFELY

1. Modern ammunition uses smokeless powder as the energy source. Smokeless powder is much more powerful than black powder or Pyrodex. Never substitute smokeless powder for black powder or Pyrodex and never mix it with either.

2. Follow all loading instructions exactly. Don’t substitute any components for the ones listed. Start loading with the minimum powder charge in the load shown.

3. Never exceed manufacturers reloading data at any time. Excess pressures caused by excessive loads could severely damage your rifle and cause serious injury or death to yourself or any bystander.

4. Understand what you are doing and why it must be done in a specific way.

5. Set up a loading procedure and follow it. Don’t vary your sequence of operations.

6. Set up your reloading bench where powder and primers will not be exposed to heat, sparks or flame.

7. DO NOT smoke while reloading.

8. ALWAYS wear safety glasses while reloading.

9. Keep your reloading bench clean and uncluttered. Label components and reloads for easy identification.

10. Do not eat while handling lead.

11. NEVER try to dislodge a loaded cartridge that has become stuck in the chamber by impacting it with a cleaning rod. Have a competent gunsmith remove the cartridge for you.

The photograph shows the components required to carry out successful reloading

	Sized and trimmed case
	Primer
	Bullet
	Powder

Smokeless Powder

All smokeless powders obviously have to burn very fast. You will readily note the differences in physical size and shape of various powders, but you cannot see differences in chemical composition that help to control the rate of burning. Burn rate is also affected by pressure. Hot primers, seating the bullet too deep, over crimping the case onto the bullet, tight gun chambers, oversize bullets are just some of the problems which affect pressure. This is why reloading requires attention to detail, patience and meticulousness to ensure the safety and quality of your reloads.

Never mix powders of different kinds.
Use the powder ONLY as recommended in manufacturers reloading manuals.
Store powders in cool a dry place.
If you throw or measure powder charges by volume, weight check the charges every time you begin loading, occasionally during loading and when you finish.
Pour out only enough powder for the immediate work.
NEVER substitute smokeless powder for black powder or Pyrodex.
Don’t carry powder in your pockets; wash your hands thoroughly after handling it.
Store powder only in its original containers.
Keep powder containers tightly closed when not in use.
Smokeless powders are EXTREMELY FLAMMABLE; great care must be taken when disposing of them.
Empty the powder measure back into the original powder container when through with a reloading session.
Clean up spilled powder with a brush and dust pan NOT a vacuum cleaner because a fire or explosion may result.

Primers

Priming materials differ in brisance (initial explosive force) and in the amount of hot gas produced. Don’t mix primers of different makes.
Don’t decap live primers, fire them in the appropriate rifle then decap.
Don’t ream out or enlarge the flash hole in the primer pockets. This could increase chamber pressure.
Over ignition creates high chamber pressures. The best results are obtained by using the mildest primer consistent with good ignition.
Don’t use primers you cant identify.
Keep primers in the original packaging until required. Return all unused primers to their original package. Don’t bump together or store in bulk, there is a risk of mass detonation if one is ignited.
If resistance to seating or feeding of primers is felt, STOP and investigate. DO NOT FORCE PRIMERS.
Store primers in a cool dry place. High temperatures will cause them to deteriorate.
Don't handle primers with oily or greasy hands, oil or grease can affect ignitability of the primer

Photograph shows a RCBS loading block holding 40 inspected, trimmed, sized and primed cases ready for reloading

Handloading Rifle Cartridges

Clean and examine cases before loading. Discard any that are in poor condition. The case shown in the photograph shows case neck damage (this case is a new one, make sure you check every case before any reloading commences) and needs binning.
Put labels on boxes of newly loaded cartridges. Identify calibre, primer, powder and charge weight, bullet type and weight and date of reloading.
Check the overall length of the cartridge to be sure the bullet is seated properly.
The photograph shows a new unfired case which clearly shows neck damage remember check and check again and bin any damaged cases. NEVER consider using any case showing damage of any kind.

Prevent Missing and Double Charges

It is easy to double charge if your concentration is disturbed. Use a depth gauge to check the powder height in the case.
Observe the powder level of cases placed in the loading block. This is a good way to check for double or missing charges.
Take care to operate progressive presses as the manufacture recommends. Don’t back up the turret or juggle the handle, don’t use a cartridge case to catch the residue when cleaning out the powder train.

Reloading Procedures

The reloading procedure can be as simple as putting the correct charge of powder in s sized case and seating a bullet to SAAMI specifications, or can be made into dozens of steps taking hours of work. It depends on what kind of end results you want to achieve. Accuracy is a relative thing and what qualifies as an accurate load for one person is un acceptable to another. The definition of a good load is also different according to different people. One thing is certain; handloading will have a great influence on the performance of your rifle.

Basically, the reloading process can be divided into three main steps, with each containing other steps. The three main steps are:

Preparing and sizing the case.
Charging the case with powder.
Seating the bullet.

These steps include the following:

1. Preparing and sizing the case.

Cases must be inspected for flaws or any other damage.
Lubricate and resize the cases.
Trim case to the correct length and chamfer the neck.
Prime cases with a new primer.

2. Charging the case with powder.

A. Zero and set the powder scales.

B. Measure the powder.

C. Charge case.

D. Visually check all cases for double charges.

3. Seating the bullet.

A. Using a dummy round check the over all length (OAL) of the cartridge with the data in your reloading manual.

B. Adjust the seating stem of your press until the correct AOL is obtained.

C. When you have achieved the correct AOL lock off the locknut on the seating die.

D. Try the correct length dummy round in the magazine of your riffle and cycle the

Action to check its operation.

There are various tools and products that are available to the handloader which will be discussed in more details on the PRODUCTS PAGE.

The end product, from left to right

	308 Winchester
	7mm Remington Magnum
	6.5x55 Swedish

SPECIFIC RELOADING INFORMATION

6.5x55 - .308 Winchester - 7 mm Remington Magnum

6.5x55 :

Historical Notes

Jointly developed by Norway and Sweden, this cartridge was adopted by both countries as an official military chambering in 1894.Originally both countries loaded and used identical ammunition. Later, the Swedish modified the dimensions and loaded to a higher pressure for use in their Mauser rifles, while the Norwegians kept the original version for use in the Krag rifle. The 6.5x55 cartridge remained in service with the Swedish military until 1980. This cartridge in a good quality rifle will shoot sub- half inch groups at 100 meters, recoil is light which lends itself for accurate shooting.

Country of origin :	Sweden
Year of introduction :	1894
Primer :	large rifle
Max. bullet diameter :	6.71 mm (.264")
Max. cartridge length :	80.00 mm (3.150")
Max. case length :	55.00 mm (2.165"), trim to 54.80 mm (2.155")
Max. CIP pressure :	330 MPa (47800psi)
Max. SAAMI pressure :	46000 CUP

Data produced from the use of VIHTAVUORI powders

140 grain HPBT Sierra Matchking

Starting Load :	N150	32.6 grains	2230 fps	40600 psi
	N160	41.6 grains	2406 fps	40600 psi
	N165	43.6 grains	2447 fps	40600 psi
Maximum Load :	N150	34.8 grains	2362 fps	46400 psi
	N160	44.0 grains	2546 fps	46400 psi
	N165	46.9 grains	2626 fps	46700 psi

WARNING : start 10% lower when using maximum loads and work up in 0.1 of a grain increments do not use loads less than the starting loads.

.308 Winchester :

Historical Notes

Developed by Winchester in 1952 as a sporting cartridge, in 1954 it was adopted by the U.S.as the 7.62x51mm NATO service cartridge.

Country of origin :	U.S.A.
Year of introduction :	1952
Primer :	large rifle
Max. bullet diameter :	7.85 mm (.309")
Max. cartridge length :	71.12 mm (2.80")
Max. case length :	51.18 mm (2.015"), trim to 51.00 mm (2.005")
Max CIP pressure :	360 MPa (52200 psi)
Max SAAMI pressure :	52000 CUP

Data produced from the use of VIHTAVUORI powder

168 grain HPBT Sierra Matchking

Starting Load :	N150	41.9 grains	2429 fps	39200 psi
Maximum Load :	N150	46.1 grains	2657 fps	50800 psi

WARNING : start 10% lower when using maximum loads and work up in 0.1 of a grain increments do not use loads less than the starting loads.

7 mm Remington Magnum

Historical Notes

Introduced in 1962 it has become one of the most successful cartridges ever.

Country of origin :	USA
Year of introduction :	1962
Primer :	large magnum rifle
Max. bullet diameter :	7.23 mm (.284")
Max. cartridge length :	83.57 mm (3.290")
Max. case length :	63.50 mm (2.50") trim to63.30 mm (2.490")
Max. CIP pressure :	370 MPa (53600 psi)
Max. SAAMI pressure :	52000 CUP

Data produced from the use of RELOADER powders

145 grain HPBT Sierra Matchking

Starting loads :	Re19	63.00 grains	2948 fps
	Re22	64.00 grains	2919 fps
Maximum loads :	Re19	67.00 grains	3153 fps
	Re22	68.00 grains	3136 fps

WARNING : start 10% lower when using maximum loads and work up in 0.1 of a grain increments do not use loads less than the starting loads.

Before using hand loaded cartridges check your rifle for wear and stress, if you are not able to do this have a competent gunsmith carry out the checks for you.

The European hunter has access to many North American hunting cartridges including such favourites as the .223 Remington, .243 Winchester, .270 Winchester, 7mm Remington Magnum, .30-30 Winchester, .308 Winchester, .30-06 Springfield, .300 Winchester Magnum, .338 Winchester Magnum, and the Weatherby Magnum series. These have become world hunting cartridges. Just as those of us living in the U.K. have access to a number of European metric cartridges, such as the 6.5x55 Swede, 7x57 Mauser, 7x64 Brenneke, 7.62x39 Soviet, and 8x57S Mauser, all of which are loaded by major U.S. arms and ammunition makers.

Those metric cartridges are worldwide favourites, but some fine metric cartridges are virtually unknown here in the U.K. We have so many U.S. hunting cartridges from which to choose that I suppose this is inevitable, but there are some European hunting cartridges that should be tried. These are the cartridges that are equally as good as any U.S. ones and deserve a look at.

6x62 Freres

This is a relatively new cartridge introduced by MEN of Germany. The 6x62 significantly out performs the 6mm Remington and .243 WSSM. It is basically equivalent to the North American 6mm-06 wildcat, and just a step behind the .240 Weatherby Magnum. The 6x62 is based on the 9.3x62 case and requires a standard length rifle action.

6x62 factory loads drive an 85 grain bullet at a muzzle velocity (MV) of 3460 fps with 2260 ft. lbs. of muzzle energy (ME), and a 100 grain bullet at a MV of 3313 fps and ME of 2442 ft. lbs. These loads are effective on a wide variety of small and medium game. The 100 grain bullet seems particularly suitable for all species of U.K. and European deer. The 6x62 offers flat trajectory, good killing power, and moderate recoil.

6.5x55 SE

This is one of my favourite rifle cartridges. If I could have only one metric rifle, it would be a 6.5x55 SE. The cartridge was designed for the military use of Norway and Sweden before the turn of the 20th Century, and it has been in regular use as a sporting round ever since. The 6.5x55 has also proven itself on thin-skinned game all over the world, including Africa and North America, and garnered a reputation for killing power out of proportion to its rather modest paper ballistics. As they say, it's hard to argue with success.

6.5x55 factory loads are available from the major U.S. ammunition companies, and they are available from just about all European manufacturers. Sellier & Bellot of the Czech Republic offers a 140 grain bullet at a MV of 2645 fps, which is typical. Norma of Sweden offers a variety of hotter loads which drive 139-140 grain bullets at MV's up to 2854 fps, and 156 grain bullets at MV's up to 2644 fps with ME of 2422 ft. lbs. These loads kill well because of the deep penetration afforded by their relatively heavy bullets of high sectional density. Recoil and muzzle blast are mild, promoting accurate bullet placement.

6.5x68S Schuler

This .264 magnum cartridge was developed by RWS of Germany. In performance it is in-between the 6.5mm Remington Magnum and the .264 Winchester Magnum, and quite similar to the .270 Winchester. It is an excellent long range cartridge for all European species of thin-skinned game, and a good choice for African plains game.

European factory loads drive 123 grain bullet at a MV of 3450 fps with 3255 ft. lbs. of ME, and a 140 grain bullet at a MV of 2920 fps with 2651 ft. lbs. of ME. The 6.5x68S drives a 139-140 grain bullet of greater sectional density to approximately the same velocity as the 7x64 Brenneke (see below).

7x64 Brenneke

The 7x64 Brenneke predates the .270 Winchester by 8 years and the nearly identical .280 Remington by decades. In performance, all three of these cartridges are quite similar.

The 7x64 is a popular cartridge for African plains game with experienced European hunters.

Factory loads drive a 139 grain bullet at a MV of 2955 with ME of 2690 ft. lbs., a 154 grain bullet at a MV of 2822 fps with ME of 2772 ft. lbs., and a 173 grain bullet at a MV of 2790 fps with ME of 2990 ft. lbs.

The 7x64 offers greater bullet frontal area but less sectional density than the 6.5x68S with 139-140 grain bullets. Recoil is practically identical. They are both fine hunting cartridges, so I could not resist including both in this article. A practical hunter would probably have to flip a coin to decide between them.

8x68S

This powerful .32 caliber magnum cartridge uses a beltless case. It is the European equivalent of the 8mm Remington Magnum in terms of ballistics and application. The 8x68S was introduced by RWS just before the beginning of the Second World War. It is a powerful, long range cartridge suitable for all thin-skinned game, from red stag and Scandinavian moose to African eland.

Typical European factory loads drive a 187 grain bullet at a MV of 3180 fps with ME of 4195 ft. lbs., and a 200 grain bullet at a MV of 2985 fps with ME of 3958 ft. lbs. Needless to say, recoil is also right up there with the 8mm Rem. Mag.

9.3x62

This is a powerful .36 caliber medium bore cartridge with ballistics on the order of the .350 Remington Magnum. It was designed around 1905 for bolt action rifles, primarily for use on large and dangerous African game. It gave farmers and settlers there an alternative to expensive British and German double rifles. It has been used in Africa ever since, and has acquired a fine reputation. European hunters use it at home on big wild boar and Scandinavian moose.

Norma factory loads drive a 232 grain bullet at a MV of 2624 fps with ME of 3548 ft. lbs., and a 286 grain bullet at a MV of 2360 fps with ME of 3544 ft. lbs. Clearly, the 9.3x62 would be a fine choice for all large North American game.

Conclusion

As you can see, while the nomenclature of these cartridges is metric, the performance of these European favourites leaves nothing to be desired.

Ammunition and brass for most of these cartridges are rather expensive in the U.K. but they are available. Once you have a supply of boxer primed cases, other reloading components are no problem.

ARCANE WORLD of CARTRIDGE DESIGNATIONS

Here’s one subject that surrounds and sometimes plagues us on a daily basis. Even though we deal with ammunition in the pursuit of our hobby, interest, sport and sometimes even our profession, many of those who throw cartridge designations around rather cavalierly have no true feel for their origin or meaning. Let me take a stab at clarifying things for the newcomers (and maybe even a few old-timers) entering into the Arcane (secret) World of Cartridge Designations.

This should not be considered a definitive work on the subject, just a quick and dirty primer so you can smile to yourself and knowingly speak cartridge to the seasoned old veterans, and maybe even teach them a thing or two.

Before we get too deeply into the actual subject matter, perhaps it would be helpful to define a few terms so that we are all on the same wavelength. In this article we will be primarily concerned with metallic cartridges, of which we have several types that are familiar to most individuals interested in the shooting sports. Virtually all cases can be put in the category of straight walled cases (ex: .45 Colt, .45-70), bottle-necked cases (ex: .30-’06, .44-40), and tapered cases (ex: 9mm Parabellum, .30 Carbine). The cases can further be classified by their rim type, such as rimmed, rimless,semi-rimmed, rebated rim and belted. The outward configuration of the case such as a straight walled case is self-explanatory, but not necessarily the classification by rim style. Now, onward to the actual cartridge designation's) by calibre. Let’s start with the old timers in the cartridge world, as they will give us a few clues into the present. For instance, do you know what is meant when they speak of the .45-70, the .44-40, the .40-62 or the .30-30? These are leftovers from the days of blackpowder cartridges, and are perhaps the simplest to explain. The .44-40, simply put, referred to a .44 calibre cartridge loaded with 40 grains of blackpowder. It follows rather elementarily that the .32-20, and the .38-40, etc. simply use the calibre (designating the diameter of the bore, although usually not very accurately), followed by the number of grains of blackpowder used to propel the projectile on its way to the target. Blackpowder rifle cartridges get a bit more complicated, although once you understand the system, they too fall into a rather ordered system.I bet you thought that the .45-70 was just called the .45-70, not necessarily. They had the .45-70-405 and the .45-70-500 and even the .45-70-300. The third numerical designation represents the bullet weight in grains. For instance, the U.S. Service load for the Trapdoor Springfield came in two flavours. The .45-55-405 was the load used by the Calvary in the Carbines, and the .45-70-500 was the Infantry load. Both cartridges were interchangeable as far as chambering and firing in the Trapdoors, but the 500 grain projectile propelled with 70 grains of blackpowder, while perfectly safe to fire in the carbine, was a "bit" uncomfortable to shoot in the shorter and lighter of the two weapons. Complaints from the Calvary troopers resulted in the 405 grain projectile propelled by a load of 55 grains of powder.

Think you’ve got it now? Let’s throw a little extra stuff in the game. What about the Sharps and rolling/falling block cartridge designations. We have, for instance, the famous target cartridge, the .45-120-3 ¼ (usually pronounced, the forty five by 120 by 3 ¼). Here we’re talking about a .45 cartridge using a load of 120 grains of blackpowder contained in a cartridge case 3 ¼" long. Even the .45-70 was sometimes referred to as the .45-70-2 ¼.

Now that we have covered the hyphenated cartridge designations, we come to a grey area that occurred during the transition from black to smokeless powder. Utilizing the tried and true precedents, when the .30-40 Krag was introduced as the new service cartridge in the early 1890s, a real dilemma reared its ugly head. Blackpowder was simply blackpowder utilizing essentially the same formula and having the same characteristics, with the burning rates controlled by the size of the powder grains. The larger the grain, the slower it burned. For instance, FG (large powder grains, designed primarily for rifles) burned slower than FFG and FFFG (pistol powder) or FFFFG (priming powder). The more Fs the smaller the grains and the faster it burned, but the quantity used was not nearly as critical with black powder as it was with smokeless powder. If you inadvertently used 70 grains of triple F in a .45-70, the dirty burning, smoky, foul smelling stuff was pretty forgiving, blackpowder being a mechanical mixture. Conversely smokeless powder is a powder produced by chemical reaction's and usually has widely varying burning rates from powder designation to powder designation. For instance a load of 42 grains of IMR 4895 might be perfectly safe in the .308 Winchester, but 42 grains of Bullseye will make you a prime candidate for harp lessons. The original .30-40 Krag cartridge used a .30 calibre projectile propelled by 40 grains of smokeless powder – the question was WHAT smokeless powder?! This carried over for one last try in the designation of the Thirty-Thirty Winchester that has become almost an American icon. The coming of smokeless powder spelled the doom of the hyphenated cartridge designations. You can imagine the problems that would be encountered if you spoke of the .308 Winchester as the .30-42! The question would immediately be forty two grains of WHAT?"

As a quick aside, for many years, the service cartridge designations were followed by the descriptive term Government, as in the.45-70 Government. The last gasp at attempting to call the (then) current service rifle cartridge the .30 cal. Govt. was directed at the original cartridge utilized in the U.S. Magazine Rifle Model 1903, sometimes (now) called the .30-’03. Originally it (the 220 grain round nosed load) was known as the .30 Government, but then the .30-40 Krag had also been called the .30 Government upon occasion (most especially when it was listed as a cartridge chambering option in the Model 1895 Winchester lever gun). Throwing up their hands in dismay, the Army Ordnance folks decided to name the new replacement cartridge for the M1903 the .30-’06. This of course stood for a .30 calibre cartridge adopted in 1906. The designation of .30-’03 was an after the fact designation for the original 220 grain bulleted cartridge initially used in the ’03 Springfield to differentiate it from the then new .30-’06. Simply calling the former cartridge the .30 Government was a little confusing since there was two of the blighters hanging around often using the same designation.

How about the early service pistol rounds? the first full-blown official metallic pistol round was known as the .45 Colt (since it was developed by Colt, it seemed only fair I suppose). All went without a hitch until a certain Col. Scofield came into the picture. He was much impressed with the break-top loading and ejecting system utilized by Smith and Wesson. This system, he felt would be a much better and faster system for the galloping Cavalryman to reload aboard a horse than the somewhat laborious side loading and ejecting system of the Colt. While he no doubt had a point, S&W chose to utilize their standard big bore top break pistol frame, which was a bit short to accommodate the full length .45 Colt Cartridge. S&W designed the Scofield Smith to use a cartridge they called the .45 S&W. The U.S. Army bought a number of these pistols in 1877 and they were issued and essentially interspersed with the venerable Colt with no thought of the ammunition problem they were creating. Much like the .38 special which will chamber in the .357 Magnum, but not vice versa, so it was with the .45 S&W and the .45 Colt. To solve this dilemma, the U.S. government simply adopted the .45 S&W as standard and called it the .45 Government Pistol Cartridge. This rather interesting solution has resulted in a cartridge misnomer that has lasted for over 100 years. Virtually everyone has heard the .45 Colt called the .45 Long Colt, but of course as you now know, that is not and has never been the official name of the .45 Colt cartridge. As the Scofield models found their way into the civilian market in the late 1800s (Wells Fargo even used some of them), the owners had to come up with suitable fodder for their sidearms. Walking into the local gunsmith’s or hardware store asking for a few .45 pistol cartridges would no longer do. Those using a .45 Peacemaker didn’t want the less powerful .45 S&W stuff when going in harm’s way, even though they would shoot just fine in their Colt self-protection hardware. Thus it became customary to call the Peacemaker round "The .45 Long Colt" to differentiate it from the shorter S&W round.. The .45 S&W cartridge has long since disappeared from the scene, but the misnomer of .45 Long Colt seems to survive despite all attempts to educate its users to the fact that they are really using the .45 Colt, well, some things are so ingrained as to defy common sense and education. To make matters even more confusing, there was even a third .45 Government round (this time of full .45 Colt length) designed for revolvers, and would chamber in the standard .45 Colt chamber. The only problem was that the cartridge rim was larger in diameter than the original (commercial) .45 Colt. This version of the .45 Colt was produced at Frankfort Arsenal (and perhaps other government locations) it was never a commercially available cartridge. The reason for this version's existence was tied in to the U.S. military experience in the Philippines around the turn of the century. Almost everyone has heard of the rather dismal performance of the .38 calibre pistols issued to the military at that time. When the military turned in the old .45 thumbuster Colt single actions they came up with a marvellous little double action pistol in a calibre which was essentially a rather underpowered version of the .38 Special. A call for help from the deployed forces resulted in many of the old .45 single actions being broken out of storage and shipped to the Philippines along with some of the later 1877 Colt Double Actions in the same calibre. The Philippine experience resulted in the Thompson-Legard Tests that recommended a service pistol calibre of no less than .45 calibre. The U.S. Government was then experimenting with adopting a semi-automatic pistol, but a final design had not yet been adopted in 1909. Anxious to give the troops adequate pistol power, the government adopted an interim "fix" to the problem. They contracted with Colt to produce a Government version of the New Service Colt in .45 Colt calibre, and designated it the Model 1909. There were versions of the 1909 Model marked U.S. Army, U.S. Navy and even a round butted version marked U.S.M.C. As all of you know who have any experience with the .45 Colt Cartridge, one of its weaknesses is the rather narrow rim that had sometimes given extraction problems in the blackpowder days with the Single Action on the frontier. That coupled with the fear that the narrow rim would give extraction problems with the ejection star of a new swing out cylinder double action, caused the designers of the new interim revolver to remedy the problem by modifying the old .45 Colt cartridge and giving it a wider case rim. Needless to say it worked just fine in the new Model 1909s, but if you tried to load it into the Colt Single Actions of the same calibre (which had a cylinder that was smaller in overall diameter) the rims would interfere with one another and would only allow you to load every other chamber (interestingly enough, the 1909 worked just fine with a standard .45 Colt cartridge)! The new U.S.government version of the .45 Colt round went the way of the Do-Do Bird with the coming of the new 1911 Colt.

How about the pistol cartridge designations ending in ACP? For instance, we have the .25 ACP, .32 ACP, .38 ACP and the .45 ACP. These are simply an abbreviation for Automatic Colt Pistol, and were named for the Company that designed and built the (original) pistols to fire the cartridge. The cartridge designations were proprietary but not limited to pistols designed only by Colt. It is quite common for many handguns to utilize the .45 ACP, although built by S&W, Glock, SIG, etc. The ACP simply is a "doff of the hat" to the origins of the cartridge. Many other cartridges are linked to their originators, such as the .357 Magnum (officially the .357 S&W Magnum). The word Magnum is registered to S&W and must be so identified when listing the cartridge, even if the pistol happens to be a Colt Python (using the S&W .357 Magnum cartridge – take a look sometime!). You really get into an intertwinement of terms with the .44 Remington Magnum (the official designation of the Dirty Harry cartridge). Here we have Remington as the originator of the cartridge, but then they (the folks at Remington) were working hand in glove with S&W who was working to produce the pistol that Remington was designing the ammunition for. Or how about actual bore size? In the United States, the bore size is usually designated in hundreds (or even thousands) of an inch. That would be great if everyone had stuck with the original plan, but it got badly corrupted in the 1800s. The .44 Cap and Ball revolvers were usually .45s (going somewhere between .451 up through .457 in the case of the Ruger "Old Army") and the .36 Navy guns were close to .38 calibre. The original .45 Colt had a bore diameter of .454, but this has been reduced to .452 in modern versions of the Colts and S&Ws. Most .32 Autos are really .30 calibre, and the .38-40 goes closer to a true .40. The Colt versions of the .357 are closer to a .356, while S&W sticks to the original .357. The 9mm runs from.355 to .356 depending on the make of the pistol and/or barrel. The .38 S&W Special ( there is also a Colt .38 Special also) is really a .357 in bore diameter, and so it goes. The so-called .44 Specials and the .44 Magnum are really closer to being .43s (.429). The .45 ACP has always been a .452, and has now been joined by the .45 Colt since they came down from a .454. It’s always a good idea to slug the bore on your .45 Colt if you are handloading lead pistol bullets if you want maximum accuracy or are pushing the envelope of maximum load development… sometimes a millimetre will make a very large difference in accuracy and safety! Some of the modern Single Actions copies made in Europe vary a bit on their bore and cylinder sizes; better to be safe than sorry!

Then there is a couple of other oddities; we have the .250-3000 which is a .25 calibre that was supposed to have a muzzle velocity of 3000 fps, and the .30-338, which is a .338 case necked down to .30 calibre, or the 8mm-’06 which is a .30-'06 necked up to 8mm, or the .358 Winchester, which was a .308 also necked up to .35 calibre. This was a modernization of the old .35 Whelen, which was simply a.30-‘06, also necked up to .35 calibre. It seems that no one is ever satisfied. Generally speaking, when you see a cartridge with a hyphenated designation of two calibres, with the first number indicating a larger size than the original case (338-’06 or 8mm-‘06) it indicates a cartridge that has been created by necking-up an existing cartridge. Necking down doesn’t always follow the same pattern, as the .270 Winchester is a necked-down .30-’06, but on the other hand we have such cartridges as the .25-’06 which is also necked down to .25 calibre from the .30-’06.

We can also classify our cartridge cases by their profile, method of extraction, and method of chamber retention. We have rimmed cartridges (probably the oldest if you don’t count "pin-fires" or "teat-fire" cases). Under rimmed, we have "rimfire" where the priming compound is contained in the rim of the cartridge. Then we have centerfire rimmed cases (.30-30, .45-70, etc.) We have rimless cartridge cases such as the .308 or .30-’06. We have straight walled cases (.45-70, and the .38 Special), and then we have bottle-necked cases (again.308 or .30-’06 are good examples). …And of course we have "belted cases" (designed to headspace on a case belt located just forward of the case rim, as opposed to the shoulder of the case or the rim of the case itself - a quick example here is the .300 Win Mag.). We have semi-rimmed cartridges (.38 Super) and rebated cases (cases with a rebated rim) such as the .41 Action Express or .50 Action Express (usually abbreviated as the .41 AE, and .50 AE respectively). The rebated rims are usually designed to use a slide face designed for a smaller round so that you can use the existing extractor without changing slides on a semi-auto pistol (a .41 AE barrel will usually drop right into a 9mm pistol slide and sometimes (but not always) even use the same magazine, thus making a pistol with a convertible calibre by simply changing barrels). We haven’t even touched on the Berdan vs. Boxer Priming systems yet, or even corrosive as opposed to non-corrosive primers.

Okay, now that you are getting used to the fact that cartridge designations in the U.S. are a bit "iffy" (but at least understandable if you do your homework), let’s take a look at the European designations. Until WWI very few Americans (with the exception of a few big game hunters who went on safaris on the Dark Continent) came into contact with the European cartridges. The Great War changed all that, many of them brought home souvenirs of the 8mm Mausers picked up on the battlefield while saving the World for Democracy. While we British had followed the same general cartridge designation system as the United States (or the other way around) in using bore diameter expressed in hundreds or thousands of an inch; the ever-meticulous Germans had designated their bore diameters utilizing the metric system. The 8mm (actually a 7.92mm) followed this pattern, as they did firearms calibre designations in France and Belgium (the 8mm Lebel, etc.). The Germans even differentiated the length of their calibres by adding the designation of "Kurtz" (meaning short). For instance the small 7.92mm bottle-necked cartridge designed for the MP44 Assault Rifle was called the 7.92mm Kurtz as opposed to the longer standard German service round. In Europe, the little .380 ACP pistol cartridge is known as the 9mm Kurtz. The standard German pistol cartridge was the 9mm Parabellum (meaning "for war", but usually called the 9mm Luger in this country); and of course the famous Luger Pistol also came in the 7.62mm Luger caliber. Even though the U.S. had tested the 9mm Parabellum Pistol at the turn of the century, the decimal system of bore designation never caught on. It wasn’t until the U.S. involvement in NATO that the U.S. designated their service cartridge in millimetres. This was done of course, to preclude confusion in the re-supply of ammunition in a combat environment in the event of a war in Europe.

The 7.62mm NATO Cartridge is the NATO designation for the experimental T65 cartridge. Immediately following WWII the U.S. had been working on a new service rifle cartridge to replace the old .30-’06. The new cartridge was designed to take advantage of the efficiency in modern smokeless powders not available at the time of the adoption of the .30-‘06. The new T-65E3 experimental cartridge had the nominal ability to extract the same paper ballistics out of a case ½" shorter than the old ought-six. This cartridge development was done in conjunction with the production of a new lightweight service rifle (that became the M14). The M14 and the T-65E3 cartridge were an excellent combination that the United States Ordnance people were most pleased with. The fly in the ointment was that several other countries were also developing new cartridges and were vying to have their new rounds adopted as the NATO standard. History notes that U.S.prevailed, but not without giving some concessions to their NATO Allies. The first (and perhaps worst) was that the U.S. agreed to adopt the 9mm as our standard pistol round (with the proviso that they would do so as soon as we adopted a new pistol – something that they mercifully didn’t get around to until 1985). The second was that we couldn’t call the cartridge the .308 Winchester or T-65 as the experimental government version was called (the .308 Winchester was simply a commercial knock-off of the newly developed Government round). They were required to use the official designation of 7.62mm NATO. This was really an exercise in semantics, as 7.62mm converted to inches is .308" in diameter. The Europeans also have one other maddening habit; they tend to add a few numbers to the cartridge designations to designate the length of the cartridge. For instance, the (full) official European designation for the 7.62 NATO is the 7.62 X 51, meaning the bore diameter is 7.62mm in diameter with a cartridge case length of 51mm. The official 9mm NATO is actually a 9 X 19, indicating a 9mm bore and a case length of 19mm.Being an engineer by profession, it’s not that I don’t appreciate precision but when it comes to certain things, I’m hopelessly old fashioned. I like my shirt sizes in inches, my road travel distances and speed limits in miles and miles per hour and my bore diameters inches

Let us now look at some of the more Arcane British cartridges for instance the 297/230 Morris Short, Long, Extra Long and Lancaster Sporting all with as much power as good catapult. The 297/250 Rook slightly more powerful, but why not use a shotgun instead. There is still the 300 rook,360 No 5 rifles (whatever happened to Nos 1,2,3 and 4).There is also the popular .303, jacketed bullet diameter for the .303 is .311inch and cast bullets can be .312 to .313 inch nothing is as simple as it sounds. There are many more examples to consider, for a later time perhaps.

LETS TALK ABOUT RECOIL

Recoil is generally expressed as free recoil and measured in foot-pounds of energy. Free recoil means that the rifle is allowed to move backward unrestrained after being fired. If something (like your shoulder) restrains the rifle's rearward motion, then your shoulder must absorb the energy generated by the recoiling rifle. Bummer!

Recoil is measured in something called a recoil pendulum, or calculated by mathematical formula based on Newton's physical law that says for every action there is an equal and opposite reaction. MV = MV (mass times velocity equals mass times velocity), the momentum must be equal on both sides of the equation. Newton's law explains why rocket motors are able to propel the space shuttle into orbit, and why guns kick.

The principle factors that must be considered to calculate recoil are bullet weight (mass), bullet velocity, powder charge, and rifle weight (mass). The mass times the velocity of everything ejected from the muzzle of a rifle (principally the bullet and power gasses) will be equalled by the mass times the velocity of the recoiling rifle.

The majority of authorities seem to agree that recoil of over 20 ft. lbs. will cause the average shooter to develop a flinch, which is ruinous to accuracy. I estimate that about 15 ft. lbs. of recoil energy represents upper limit of the average shooter's comfort level. Above that recoil becomes increasingly intrusive. The effects of recoil are cumulative. The longer you shoot, and the harder a rifle kicks, the more unpleasant shooting becomes and the more likely you are to jerk the trigger or flinch.

The free recoil velocity is how fast the gun comes back at the shooter. The faster a gun comes back at you the more it hurts. This is because your body has less time to give with the recoil. You have probably heard about the long, slow push touted by some big bore fans as opposed to the sharp rap supposedly delivered by high velocity cartridges. Recoil velocity is a real, measurable effect. But the long slow push appears to be a myth. Both my own personal experiences with a reasonable range of rifle calibres from .22 LR to 470 N.E. and a quick perusal of the Rifle Recoil Table will show that the recoil velocity tends to increase as the recoil energy increases. The following examples of recoil energy and velocity are all measured in 8 pound rifles. (Calibre [bullet weight, muzzle velocity] = free recoil energy & free recoil velocity.)

	6mm Rem. (100 grain, MV 3100 fps) = 10.0 ft. lbs. & 9.0 fps
	.270 Win. (140 grain, MV 3000 fps) = 17.1 ft. lbs. & 11.7 fps
	.30-06 (180 grain, MV 2700 fps) = 20.3 ft. lbs. & 12.8 fps
	.35 Whelen (250 grain, MV 2400 fps) = 26.1 ft. lbs. & 14.5 fps
	.450 Marlin (350 grain, MV 2100 fps) = 35.7 ft. lbs. & 17.0 fps
	.458 Win. Mag. (500 grain, MV 2050 fps) = 68.9 ft. lbs. & 23.5 fps

In the typical examples above, as the bullet weight goes up the muzzle velocity (MV) goes down; but the recoil energy and recoil velocity both continue to go up. The heavy bullets at relatively low velocity do not deliver a long slow push, they deliver a progressively harder and faster blow to the shooter. Note that the high velocity .270 with its 140 grain bullet has a recoil velocity of only 11.7 fps, while the relatively low velocity .450 Marlin with its 350 grain bullet at 2100 fps has a recoil velocity of 17 fps!

Rifle weight plays an important role in determining the amount of recoil delivered to the shooter's shoulder. For any given calibre and load, a lighter rifle kicks more than a heavier rifle. Which is why I avoid ultra-light rifles. Here are a couple of examples showing the effect rifle weight has on recoil energy and velocity when shooting the exact same load.

	.300 WSM (180 grain, MV 2950 fps), 6.5 lb. rifle = 30.8 ft. lbs. / 17.5 fps
	.300 WSM (180 grain, MV 2950 fps), 8.5 lb. rifle = 23.6 ft. lbs. / 13.4 fps

	.45-70 (300 grain, MV 1900 fps), 7.0 lb. rifle = 26.6 ft. lbs. / 15.6 fps
	.45-70 (300 grain, MV 1900 fps), 8.5 lb. rifle = 21.9 ft. lbs. / 12.9 fps

You can do your shoulder a favour by avoiding lightweight magnum rifles and guide guns. If you plan to do much shooting, get standard weight rifles. The Rifle Recoil Table, has recoil energy and velocity figures for a great many rifle cartridges fired in rifles of typical weight.

This is all well and good for theoretical models, but in reality the shooter's perception of recoil is influenced by the free recoil energy and the free recoil velocity his or her body must absorb and the shooter's pain threshold plus other factors. Some of these include stock fit, the size and shape and consistency of the rifle's recoil pad or butt plate, muzzle brake (if any), and even action type in the case of a gas operated autoloader. Muzzle blast subjectively seems to increase recoil, although it has no actual bearing on the free recoil. If the shooter is only wearing a light shirt the kick will feel worse than if he is wearing a heavy jacket or padded shooting vest.

Some of the factors that influence subjective recoil can be controlled. Wear a padded shooting vest at the range, and always wear ear protection when shooting. Have your rifles fitted with efficient recoil pads if they were not supplied that way by the manufacturer.

When shooting, pull the rifle firmly against your shoulder. Do not let it get a running start at you. Severe bruising or even a broken collar bone can result from holding a hard kicking rifle (especially something like a .375 or .470 N.E.) away from your shoulder.

Keep range sessions with powerful rifles short. Fire a group and then give yourself a break. When testing a powerful rifle I like to alternate between it and a mild kicking rifle (like a .243). I shoot a group with one rifle, then a group with the other. I seldom shoot more than one box of (20) cartridges through a hard kicking rifle during one range session, and half a box is better.

There are devices that can be added to rifles to reduce recoil. Muzzle brakes are one such accessory, and they come standard on some hard kicking rifles. They reduce recoil by redirecting the escaping powder gas to the side and rearward. Everything that leaves the barrel adds to the recoil, which in the case of a rifle is the bullet and the gasses that propel it down the barrel. (A sabot, should one be used, also adds to the recoil.) The jet effect of the escaping powder gasses makes up about 25% to 50% of the total recoil of a modern rifle. An efficient muzzle brake can reduce the actual recoil by about 20% in some cases (the figures vary widely).

The dark side of muzzle brakes is that they dramatically increase muzzle blast. In fact, with every shot they typically cause permanent hearing loss even if the shooter is wearing normal ear protection. The effect on unprotected bystanders is even worse. For this reason muzzle brakes are not appropriate for most hunting rifles and most hunting conditions. Many guides and outfitters will not permit a sport to use a rifle equipped with a muzzle brake. Some African countries prohibit their use by law.

Another recoil control device is the mercury filled or weight and spring loaded anti-recoil tube. These devices are usually mounted in the buttstock of a rifle or shotgun and help to reduce perceived recoil in two ways. First, they add weight, which actually reduces recoil. (The same benefit can be achieved by packing the butt with lead shot.) And second, the mercury or the spring loaded weight in the tube (depending on the type of tube installed) moves forward under recoil as your body is driven back, temporarily storing some recoil energy. As your body begins to recover from the rifle's recoil by moving forward again, the mercury or weight is moved back to its starting position, dissipating the stored energy. The net recoil energy is the same, but its peak amplitude is lower and its duration is longer. The subjective result is perhaps a 20% reduction in recoil.

Gas operated semi-automatic rifles also reduce perceived recoil by spreading it over a longer period of time. Rifles like the Browning BAR and Remington 7400 are an excellent choice in powerful calibres and for recoil sensitive shooters. The Remington is available in standard calibres up to .30-06; the Browning is also available in standard calibres, and adds 7mm Magnum, .300 Magnum and .338 Magnum to the list.

Always take pains to see that any new rifle has a stock that fits you. A length of pull that is too short; a small or hooked (rifle) buttplate; excessive drop at comb and heel; or a comb that it too high, particularly if it is also thin, can all be poison. A good example of a very poorly designed rifle stock (from the standpoint of efficiently minimizing recoil) is the famous flintlock Kentuckyrifle. These traditional stocks incorporated most of the negative features mentioned above. Obviously, these stocks were not designed for powerful rifles!

The modern classic stock, which features a nearly level comb designed to transmit recoil in a straight line to your shoulder and minimize muzzle jump, tends to keep the comb from rapping the shooter's cheek bone. The Weatherby magnum stock uses a Monte Carlo comb with a cheekpiece that slants down from back to front (rather than down from front to back like a Kentucky rifle) to move the comb away from the shooter's face during recoil. Both of these designs handle heavy recoil pretty well.

Rifles in calibres that generate heavy recoil, from about .375 H&H on up, should have their forward sling swivel mounted below the barrel, forward of the forearm. This is done to protect the shooter's fingers. With really hard kicking rifles the forward sling swivel, if mounted to the forearm, can injure the hand when the rifle slams back.

Thumbhole stocks should be avoided on hard kicking rifles. They are not only ugly; they can be dangerous. The recoil of a powerful big bore rifle exceeds the strength of the thumb joint; firing such rifles can hyper-extend, dislocate, or even break the thumb.

A special stock designed specifically to minimize the effect of recoil is the A-Square Coil Chek. This stock was designed as a cooperative effort between a weapons system engineer, an orthopaedic surgeon, a muscle internist, and an anthropologist specifically for rifles chambered for magnum and powerful, big bore (over .40 calibre) cartridges.

It features an exceptionally wide butt pad that distributes recoil over a large area and helps to support the rotator cuff muscle. The Coil Chek stock also incorporates a specially shaped pistol grip that helps the shooter's master hand to retain a secure grip on the stock during recoil; this allows the right arm to absorb some of the recoil energy. The comb of this stock is designed to fully support the shooter's face and retain it in the same location on the stock during recoil to prevent violent snapping of the head and neck, minimizing the possibility of headache, whiplash, neck injury, or retinal separation. The forearm of the Coil Chek stock is designed so that the thumb and fingers of the shooter's hand do not slip or lose their grip during recoil, thus also helping to absorb and control recoil. This stock is said to reduce perceived recoil by up to 50%.

Whatever the approach, recoil is an unavoidable by-product of shooting and must be managed. Proper bullet placement is the principle factor in killing power, and consistent bullet placement is not possible if the shooter jerks the trigger or flinches because of his or her rifle's recoil. The best advice I can give is to select a rifle in a calibre that is within your basic recoil tolerance, and then further reduce the subjective effect of its recoil by fitting good quality muzzle brake.

Cartridge (Wb@MV) Rifle Weight Recoil energy Recoil velocity

.17 HMR (17 at 2550) 7.5 0.2 n/a

.204 Ruger (33 at 4225) 8.5 2.6 4.4

.22 LR (40 at 1165) 4.0 0.2 n/a

.22 WMR (40 at 1910) 6.75 0.4 n/a

.22 Hornet (45 at 2800) 7.5 1.3 3.3

.222 Rem. (50 at 3200) 7.5 3.0 5.1

.223 Rem. (45 at 3500) 8.5 2.6 4.5

.223 Rem. (55 at 3200) 8.0 3.2 5.1

.22-250 Rem. (55 at 3600) 8.5 4.7 6.0

.220 Swift (55 at 3800) 8.5 5.3 6.4

.223 WSSM (55 at 3850) 7.5 6.4 7.4

.243 Win. (75 at 3400) 8.5 7.2 7.4

.243 Win. (100 at 2960) 7.5 8.8 8.7

6mm Rem. (100 at 3100) 8.0 10.0 9.0

.243 WSSM (100 at 3100) 7.5 10.1 9.3

.240 Wby. Mag. (100 at 3406) 8.0 17.9 n/a

.257 Roberts (117 at 2650) 8.0 9.0 n/a

.25 WSSM (120 at 2990) 7.25 13.8 11.1

.25-06 Rem. (120 at 3000) 8.0 12.5 10.0

.257 Wby. Mag. (120 at 3300) 9.25 15.1 10.3

6.5x55 Swede (140 at 2650) 9.0 10.6 8.7

.260 Rem. (140 at 2750) 7.5 13.6 10.8

6.5mm Rem. Mag. (120 at 3100) 8.0 13.1 10.3

6.5x68 S (140 at 2990) 8.5 16.8 11.3

.264 Win. Mag. (140 at 3200) 8.5 19.2 12.1

.270 Win. (130 at 3140) 8.0 16.5 n/a

.270 Win. (150 at 2900) 8.0 17.0 11.7

.270 WSM (150 at 3000) 8.0 18.9 12.3

.270 Wby. Mag. (150 at 3000) 9.25 17.8 11.1

7x57 Mauser (139 at 2800) 8.0 14.0 10.6

7mm-08 Rem. (140 at 2860) 8.0 12.6 10.1

.280 Rem. (140 at 3000) 8.0 17.2 11.8

7mm Rem. SAUM (160 at 2931) 8.0 21.5 13.2

7mm WSM (160 at 3000) 8.0 21.9 13.3

7mm Rem. Mag. (140 at 3150) 8.0 19.1 12.4

7mm Rem. Mag. (150 at 3100) 8.5 19.2 12.1

7mm Wby. Mag. (140 at 3300) 9.25 19.5 11.7

7mm Ultra Mag. (160 at 3200) 8.5 29.4 n/a

.30 Carbine (110 at 1990) 7.0 3.5 5.7

.30-30 Win. (150 at 2400) 7.5 10.6 9.5

.30-30 Win. (170 at 2200) 7.5 11.0 9.7

.300 Sav. (150 at 2630) 7.5 14.8 n/a

.308 Win. (150 at 2800) 7.5 15.8 11.7

.308 Win. (180 at 2610) 8.0 17.5 11.9

.30-06 Spfd. (150 at 2910) 8.0 17.6 11.9

.30-06 Spfd. (180 at 2700) 8.0 20.3 12.8

.300 Rem. SAUM (180 at 2960) 8.25 23.5 13.6

.300 WSM (180 at 2970) 8.25 23.8 13.6

.300 Win. Mag. (180 at 2960) 8.5 25.9 14.0

.300 Wby. Mag. (150 at 3400) 9.25 24.6 13.1

.300 Ultra Mag. (180 at 3230) 8.5 32.8 15.8

7.62x39 Soviet (125 at 2350) 7.0 6.9 8.0

.303 British (180 at 2420) 8.0 15.4 11.1

.32 Spec. (170 at 2250) 7.0 12.2 10.6

8x57 Mauser (170 at 2360) 8.0 12.9 n/a

.325 WSM (200 at 2960) 8.0 32.8 16.2

8x68 S (150 at 3300) 8.5 25.3 13.9

.338-57 O'Connor (200 at 2400) 8.0 19.2 12.4

.338 Win. Mag. (250 at 2700) 9.0 33.1 15.4

.340 Wby. Mag. (200 at 3100) 10.0 29.6 13.8

.338 Ultra Mag (250 at 2860) 8.5 43.1 n/a

.357 Mag. (158 at 1650) 7.0 4.7 6.6

.35 Rem. (200 at 2050) 7.5 13.5 10.8

.35 Whelen (200 at 2675) 8.0 22.6 13.5

.350 Rem. Mag. (200 at 2700) 8.5 22.3 13.0

9.3x62 (270 at 2550) 8.5 33.3 n/a

.375 H&H Mag. (270 at 2690) 9.0 36.1 16.1

.375 Ultra Mag (300 at 2800) 8.75 53.2 n/a

.378 Wby. Mag. (300 at 2900) 10.25 71.1 n/a

.416 Rem. Mag. (400 at 2400) 10.0 52.9 18.5

.416 Rigby (400 at 2400) 10.0 58.1 19.3

.44 Rem. Mag. (240 at 1760) 7.5 11.2 9.8

.444 Marlin (240 at 2400) 7.5 23.3 14.2

.450 Marlin (350 at 2000) 7.0 37.2 18.5

.45-70 (300 at 1800) 7.0 23.9 14.8

.45-70 (405 at 1330) 7.5 18.7 12.7

.458 Win. Mag. (500 at 2100) 9.0 62.3 21.1

.460 Wby. Mag. (500 at 2600) 11.25 99.6 n/a

Can The Mystery Be Solved!

Handloading readers have doubtless heard of a term called secondary explosion effect (S.E.E.). It is a theory that attempts to explain the catastrophic failure of some rifles while firing seemingly reasonable handloads or reduced loads using slow-burning powders. Theories have been offered and debated in these pages and elsewhere, but they have been just that, theories, because no one has been able to reproduce the effects under laboratory conditions. The purpose here is not to debate S.E.E. but rather to report on a specific incident and the results of tests done to discover the cause of the catastrophic failure.

2.) One of the great problems with attempting to theorize on the cause of catastrophic failures is that we must do so after the fact. We have the corpse, usually with some parts missing, and must try to figure out what went wrong. Learned theories are offered, sometimes conflicting, and we end up with a bunch of folks shouting in print, you’re wrong. No, you're wrong. Since the event they're arguing about took place without benefit of instrumentation, either one could be right. The events described here represent the first instance of an event produced under controlled laboratory conditions and documented on industry standard pressure measuring equipment that provides a plausible explanation for some of the theories offered to explain S.E.E.

3.) The following is simple. It goes all the way back to shooting, where they learned that bore obstructions blow up guns. There are no explosions, no mysterious wave amplifications; it's just a case of several factors, combining in worst case conditions, to create a bore obstruction with the bullet.

4.) In early 1992 a major ammunition manufacturer began development of a load for the 6.5x55mm Swedish that was to be added to their product line. Development was uneventful and all work was done using the copper crusher pressure measuring system, for there were no standards established for piezoelectric pressure measurement in the 6.5x55mm. The copper crusher method of pressure measurement has been with us for generations, but it is not without its limitations. The results obtained are not true maximum pressures, and it provides only a single data point. There is no way that one can deduce what is happening during the period the powder is burning, nor can one see other significant ballistic events.

5.) A quantity of ammunition was loaded using a relatively slow- burning, non-canister propellant with a 140-grain bullet. After load development in ammunition manufacturers pressure guns, it is common practice to function test ammunition in a variety of available rifles to ensure satisfactory performance before it is released for sale to the public.

6.) As function testing of the 6.5x55mm ammunition was begun using Swedish Mauser rifles, they noticed some of the same signs of excess pressure every handloader is taught to look for, flattened primers, enlarged primer pockets and heavy bolt lift. All the ammunition fired in the pressure gun had been perfectly acceptable, but SAAMI test barrels and chambers are made to tightly controlled specifications so the first supposition was that some element within the test gun was contributing to high pressures. Then a spontaneous disassembly occurred that destroyed the action but left the barrel undamaged. The bore was clear and showed no bulges. It was immediately identified as a high pressure failure and an investigation was begun. The barrel from the wrecked Mauser action was fitted with a collar that allowed it to be mounted in a universal receiver, and an industry standard conformal piezoelectric transducer was installed. Another test was performed using the Oehler Model 82 piezoelectric pressure measuring system equipped with a trace hold oscilloscope.

7.) Pressure test are commonly done with a 10-round string, and as you can see from the chart, pressures increased very gradually on rounds 1 through 4. At the fifth shot, pressure dropped and then continued to increase until, at the eighth shot, pressure went to 82,120 psi; and the technician wisely stopped the test. The raw data was then used to prepare additional graphs (fig. 1) which show that, after ignition, pressures dropped momentarily to near zero on the graph before beginning to rise again.

"Pressure Test Results"
Round	Pressure (psi)	Velocity (fps)
1 2 3 4 5 6 7 8	48,820 53,849 57,609 57,999 54,093 58,634 62,150 82,120	2,601 2,662 2,708 2,720 2,687 2,731 2,754 2,875

8.) To interpret this data we have to first understand the ground rules applicable to pressure testing with conformal transducers. The key term here is “offset” which relates, primarily, to the specific cartridge and the brass used therein and must be determined for each transducer and lot of brass. The offset is the amount of pressure required to obdurate the case to the chamber and begin to exert pressure upon the transducer. In this case the offset was 3,800 psi so when we look at the time/pressure curves produced in the test, we must understand that we are not actually seeing pressures below the level of the offset. There is a distinct pressure below the level of the offset. There is a distinct dip in the curve, however, shortly after the pressure begins to rise when it drops to a level somewhere at or below the offset pressure. All we can say for sure is that, at this point, the pressure is >= 3,800 psi. Engineers calculated that for the specific bullet being used it would take pressure of at least 5,000 psi just to keep the bullet moving.

9.) There are a number of variables at work here, but the main culprit is a very long leade or throat erosion. It takes relatively little pressure to eject the bullet from the cartridge case, which produces a significant increase in volume. Unless the rate of gas production is fast enough to keep up with the increase in volume, pressure must drop. The simple equation is P1V1=P2V2 where P = pressure and V = volume. It is helpful in considering the phenomena reported here to view the rifle barrel and chamber as a cylinder whose volume is determined by the position of the bullet at any given point in time. If the bullet is moving, the volume is continuously increasing until the bullet exits the barrel.

10.) If P2 is at or below the pressure required to keep the bullet moving it must stop. Then we run into our old friend inertia. Bodies at rest tend to remain at rest, but all the powder burning behind the resting bullet doesn’t know about that. It keeps burning and pressure rises. Sometimes we get lucky and the bullet starts to move and relieve some of that pressure, but in a worst case of a rough bore and/or soft bullet it doesn’t, and pressure continues to build until something else lets go. Most of the time this will occur around the primer pocket and gas will be released through the flash hole, but we’re talking about events that are taking place quickly (milliseconds); and if pressure rises at a rate faster than it is being relieved, a catastrophic failure is inevitable.

11.) It has been theorized that many accidents represent a combination of effects which combine, in worst case conditions, to produce a catastrophic failure. Robert Greenleaf (Rifle No. 146) presents convincing evidence to show that conditions rarely remain the same, and the condition of the barrel and throat combined with different bullet characteristics can produce markedly different pressure levels for the same load. This is certainly seen in this data where a series of eight shots of the same ammunition delivered pressures ranging, and steadily increasing, from 48,820 psi up to 82,120 psi, at which point the test was stopped. From looking at this test data, presume that all rounds (except perhaps the first) displayed some degree of temporary bore obstruction, but that the bullet was blown out of the barrel. Fortunately universal receivers are capable of containing considerable pressures, and it is certainly possible that the pressure generated by the last shot would have wrecked a standard rifle.

12.) One factor that cannot be accurately measured with this data is the possible contribution of fouling from the bullet itself. It seems reasonable to assume that some accumulated fouling was blown out on the fourth shot, which accounts for the drop in pressure at shot No. 5.

13.) When the engineers were able to examine and expand the time/pressure curve produced during this test, it became obvious that each shot showed a pronounced drop in pressure very early in the ignition/burning cycle and, on the shot where the pressure reached 82,120 psi, it dropped to the baseline before resuming a climb to the stratosphere. It would be easy to think that the fire went out, but a more reasonable explanation is that the burning rate of the powder became even slower. We know that pressure is a major component of the burning rate of any powder, and it depends upon adequate pressure levels being reached and maintained. In fact, what is shown in this case is that the amount of gas being generated was not sufficient to keep the bullet moving. If pressures drop below some optimum level, burning slows down and is often incomplete. Of course there will always be a quantity of unburned powder from any shot, and this observation has led to some of the conclusions regarding S.E.E.

14.) In order for the pressure to rise to catastrophic proportions some other adverse conditions must also be present. These involve the cartridge case, the bullet, chamber and barrel and need to be discussed individually.

15.) Bullet pull: We know that an adequate amount of tension between the case neck and bullet is a prerequisite for uniform combustion. This term, called bullet pull, is independent of the firearm and is routinely measured in the factories. Crimps may or may not be used to increase bullet pull, but most centerfire rifle cartridges depend primarily on tension between the case and bullet. If you’ve ever committed the sin of firing a cartridge into which you have neglected to dispense powder, you know that the primer alone is perfectly capable of propelling the bullet several inches down the barrel. Pressure generated by a primer alone can be as much as 4,000 psi in a conventional centerfire rifle cartridge; so it is certainly possible, in a normal round, for the primer impulse alone to be sufficient to get the bullet moving before little if any pressure has been generated by the powder charge.

16.) Chamber: In the area of the case neck there must always be some clearance between the case and the chamber wall, but if this area is too large there is little resistance and the bullet can be released with very little pressure behind it.

17.) Condition of the barrel and throat: The impact of conditions within the chamber and throat are difficult for the handloader to analyze, and a throat that appears normal under cursory inspection may be revealed to be rough and irregular when seen through a bore scope. Greenleaf’s report (Rifle No. 146) details how pressure increased as the number of rounds fired through a test barrel grew larger. This can only be attributable to a deterioration of the throat and leade on that particular barrel. In this instance SAAMI standard barrels were used and showed no irregularities, and it was only when the same ammunition was fired in a field barrel with more generous tolerances and wear in these areas that problems were seen.

18.) Bullet hardness and stiffness: The shape and construction of the specific bullet used can be a major factor in the level of pressure developed by any given load. Bullets undergo some degree of deformation as they enter the bore, and the force required for them to engrave the rifling and obdurate to bore dimensions can very considerably.

19.) Temperature: We know that pressures tend to increase as the barrel heats up, and a round that produces perfectly normal pressures from a cold barrel might show signs of excess pressure when the barrel is hot.

20.) The work presented here answers some questions. Some of the findings support theories offered to explain S.E.E., some don’t. We haven’t, for example, seen any evidence to indicate that there is ever an explosion, and many authorities doubt that there is. Perhaps what we need is a better name.

21.) Taken to its most basic component, what we have is that most fundamental cause of catastrophic failures: a bore obstruction. The difference here is that the offender is the bullet itself rather than some external source. The effect is both predictable and reproducible in the light of this new evidence, but it is highly dependent upon a combination of factors that produce disastrous results. If one or more is absent, everything will probably turn out fine; but when all come together, pressures rise and, sooner or later, something will fail. While it would appear that slow-burning powders contribute significantly, until now we didn’t exactly know what to look for. I think it’s at least theoretically possible for a bullet to stop in a barrel if the other conditions are bad enough with propellants other than the slower grades.

22.) Have you ever fired a load that you had used often and suddenly gotten signs of excess pressure such as difficult bolt lift or flattened primers, and then fired another that seemed perfectly normal? I think this happens with some frequency, and our normal recourse is to shrug our shoulders and keep on shooting; however, this could also be a bright red flag waving in front of our nose that is telling us that something is wrong. In the light of these findings, it could be telling us that a bullet did a stutter step before it went on out the barrel. The question then becomes what should we do about it. The first suggestion would be a careful investigation of the condition of the bore, especially the throat or leade to see if there is any erosion or roughness followed by thorough cleaning. A chamber cast might be in order to get precise measurements.

23.) If the barrel shows obvious signs of wear or throat erosion, the cure is obviously to replace it or set it back and rechamber. If the barrel appears to be within specifications, however, a change of bullet or propellant may be enough to solve the problem.

24.) The importance of this information is that it explains, with laboratory documentation, what can happen when the wheels fall off in the worst way. It seems like such a reasonable answer to many of the mysterious ka-booms that good reloaders have had with good handloads, and it is something we all need to keep in the back of our minds in case we encounter something out of the ordinary. While the data here was generated using the 6.5x55 Swedish cartridge, the observations are not specific to that round they could occur with almost anything.

The following is a discussion:

First off, he says the purpose of his article is not to debate S.E.E. but to report on a specific incident. But the whole of the article is to debate S.E.E. by saying the mystery is solved, we now know what causes it not that we now know what causes this particular incident.

Secondly, in the third paragraph he says that we learned in Shooting 101 that a bore obstruction with a bullet is responsible for guns blowing up. A bore obstruction of any kind whether it is from a bullet, dirt, or a cleaning patch can have disastrous consequences for the firearm, the shooter, and/or bystanders. But bore obstruction is not the only cause for a firearm to go to pieces, an over load can cause a catastrophic disassembly too. This last one builds up too much pressure before the bullet can exit the muzzle, this could look like a bore obstruction with a bullet but it is not, it is important to recognize the real culprit and that is the powder charge. In “Hatcher’s Notebook,” Major General Htcher, U.S.A., Retired, talks about the top of the receiver that was blown away leaving the bolt in place from a bore obstruction when a cleaning patch was shot out, on page 186 among others in the chapter on “experiments with barrel obstructions.”

This is where the author makes his biggest mistake. The definition of a barrel obstruction is where some physical material is blocking the path of a bullet or wading material from having an uninterrupted path through the barrel and out the muzzle. In the case of fibre filler that is acting as the wading material hitting the base of the bullet to ring the chamber, the bullet itself is acting as the barrel obstruction. If the bullet alone is involved then there is no barrel obstruction the cause, the true cause, is from something else like in the case of an over load.

Next, he says, in the fourth paragraph, “The copper crusher method of pressure measurement has been with us for generations, but it is not without its limitations. … and it provides only a single data point. There is no way that one can deduce what is happening during the period the powder is burning, nor can one see other significant ballistic events.” Well there are ways of deduce what is happening during the period the powder is burning and there are other significant ballistic events. The same way that each of use can tell rudimentary how our powder charge is behaving, and he says it later on in this article, by the weight of the bolt lift, how the primers look and fit in the primer pocket, and the amount of head expansion.

In the ninth paragraph he springs this very long leade or throat erosion on us. What is a leade or throat that can be eroded? The leade is the straight unrifled section where the chamber ends and where the lands start in an angled direction, it has the same diameter as the bullet. Some call it free bore but free bore is technically different than the leade. The throat, also known as the forcing cone in revolvers, is the angled part of the lands that starts at the forward of the leade and ends at the start of the lands that is at bore diameter. Some rifle manufacturers, like Ruger, make their rifle barrels with very long leade’s too begin with, I think excessively long.

In the tenth paragraph the author makes a statement about inertia accruing when the bullet is at rest but makes no mention about it when the bullet is moving. Inertia come into play in both cases, when the bullet is in motion it tends to remain in motion as well as at rest it tends to remain at rest; until an outside force acts upon it. In the case of it in motion the outside force is friction in stopping it, and at rest the outside force is pressure in getting it to move. In reading this article I have found that the author leaves things out to help make his position stronger on several occasions.

The author makes a very good statement in paragraph eleventh but down plays it when his says “It has been theorized that many "accidents" represent a combination of effects which combine, in worst case conditions, to produce a catastrophic failure.” In almost all tragic accidents or events it, is in the majority of the cause, is a combination of a lot of little events coming together in the right way, or should I say the wrong way. But the true cause can be ascertained but without the rest of the factors the tragic accidents or events will not take place. For example: our over load might not have taken place if one of several conditions had been changed but it will not change the fact that is was an overload that is the true cause of the problem and not a bore obstruction caused by the bullet. Let take a moment and look at the factors involved that could have been changed. Changing the bullet weight, backing off the lands, changing the powder type (relative quickness), changing the powder charge or load, any of these could make the load safe but changing the charge weight would correct any of these conditions, within limits of course.

The twelfth paragraph, had a proper investigation been done, inspection of the bore for fouling would have been on the top two of my list of thing to look for. The author also says that it is “reasonable to assume,” in my experience especially with firearms and ballistics that nothing can be assumed and everything must be experimentally and physically checked out thoroughly. In the past it was “reasonable to assume” that when the empathy of a projectile was used up the projectile would just fall, in a straight line towards the ground, out of the sky. Physics is rarely reasonable to assume, even the combined speeds of two cars travelling at 65 mph each, head on, is not 130 mph as so called common sense or reasonable to assume would suggest, but it is always less as Einstein’s law of relativity states.

In the thirteenth paragraph Mr. Petty talks about the burn-rate of powder changing with the change in pressure, this is true. The burn characteristic of any powder changes as the pressure changes and pressure is a significant part of the change in volume. While the bullet moves the volume is changing and it would not take much movement before the volume would double, halving the pressure, this can be a significant change in the powder’s burn characteristic. This movement for the volume to double is dependent upon the calibre and cartridge size. A .22 Hornet would take much less than the .22 Swift but maybe less than the .30 M1 carbine. This relationship between the powder’s burn characteristic, pressure, and volume is what makes up the “Relative Quickness” values. While in a bomb chamber, the relationship between the pressures and volume is calculated to keep the same proportions for each powder, in cartridges these proportions are not kept in balance therefore the burn characteristics of powders changes and the “Relative Quickness” can and does change with the different cartridges.

In the fourteenth paragraph Mr. Petty says, “In order for the pressure to raise to catastrophic proportions some other adverse conditions must also be present.” This is one of those statements that one can say both yes and no too. But in the context of this article we can say yes to this statement. Yes, because the load worked well in a gun system that was in prime condition.

In the sixteenth paragraph: benchrest shooters routinely shoot tight neck chambers where they must turn the necks of their cartridge cases for them to fit. They typically turn the necks to the point where there is no gap between the neck and chamber but there is also no extra pressure forcing the neck tighter on the bullet than what the neck tension is.

Relating to the eighteenth paragraph: Barnes Bullets came out with their new solid Triple shock, TSX, bullets. Barnes was getting a lot of reports of much higher pressures. Then they reintroduced the bullet but this time it had three grooves around its shank. These grooves allowed the bullet to enter and inscribe the rifling much easier lowering the pressure required to fire the bullets.

Relating to the nineteenth paragraph: This also happens when a load was worked up in winter and is shot in the summer where the temperature can be around 50 degrees hotter or more. This and hotter barrels are the primary reason that powder companies try to make their powders less temperature sensitive.

In the twentieth paragraph: There is evidence that an explosion has taken place, the disassembled wreckage of the firearm. Let me explain, there is only a slight difference between a chemical compound that can be used for propelling an object (a propellant) and exploding an object (an explosive). The difference is only in the time it takes for the chemical reaction to propagate through the chemical. The faster the propagation the more of a fragmenting effect is caused but in either case gas is given off. It is this gas that does the work. A propellant is more sensitive to pressure, the high the pressure the more gas and heat is generates, and the more gas and heat is generates the more pressure is generated, and so on…. This is very much like a thermal runaway. But the bullet travelling down the barrel keeps things in check. Steel decomposes into rust and gives off gases and produces heat, this is a form of burning very much like a propellant or an explosion but in this case the time it takes for the chemical reaction to propagate through steel is of course very slow but if it were fast enough it could be a propellant or if faster still an explosion. The term propellant is more for a legal purpose in the treatment and transportation of the chemical compound than a definition. But under normal circumstances gunpowder does not burn fast enough to be anything else than a propellant. The operative word here is “under normal circumstances.” Now what is normal? You think you know? We know and can define abnormal! But normal is impossible to know and/or define. But we can say that something is normal if and only if we place it within limits. So, we can say that gunpowder is a propellant if it’s propagation of decomposition is kept under a certain speed. And this ties directly into pressure and volume.

In the twenty-first paragraph is where we really differ in our conclusions. Mr. Petty says, “Taken to its most basic component, what we have is that most fundamental cause of catastrophic failures: a bore obstruction. The difference here is that the offender is the bullet itself rather than some external source.” What I see is not the bullet being the offender but the wrong type of powder. A powder that has too slow of a burn-rate. It cannot keep up with the components and the conditions for which it is forced to work under. One cannot reasonably say, with a straight face, that a single object can be an obstruction, that’s like saying that you got in a fight with yourself. Even in a one car accident there is another object that the car hits, a tree, fence, or the ground itself (in the case of a rollover). In this case, what is happening is the bullet was acting as if the bullet were an obstruction, but it is not an obstruction in and of itself, the true cause is the powder. This is like filling a .30-06 case full of Unique and topping it off with a 200-grain bullet and firing it, then saying that the gun had a catastrophic failures caused by a bore obstruction and the bullet itself was the bore obstruction. This effect is also both predictable and reproducible. But who is going to buy it? Yes it is also highly dependent on other factors, which is why nothing happened until thy used a degraded field barrel. I think it is not very likely that bullets routinely stop in the barrel with quicker burning powders.

I agree with what was said in the last three paragraphs.

One very simple instrument that was not used could have told the laboratory personnel exactly where and what the bullet was doing and that was the magnespectrometer. This instrument is much like the magnetometer but would have indicated when the bullet was moving, when and if it stopped, where it was in the barrel and profile it’s acceleration. But instead they rather rely on guesswork than real investigative science.

The cartridge case is the largest part of a cartridge, it contains the powder, primer and bullet. It is usually tubular in structure, closed at the base except for a primer pocket. The shape can be straight, tapered or bottle necked according to the calibre and design.

The cartridge mouth holds the bullet. The bullet is placed in the mouth of the cartridge and the mouth is then crimped, or compressed onto the bullet. The mouth of bottleneck shaped cartridge cases is often referred to as the neck.

There are six types of crimp, two of these are roll crimps.

The first roll crimp is used when the bullet is inserted completely into the case and the lip of the brass neck is rolled over with a very small radius onto a flat nose or the flange around the nose as occurs with wadcutter or Keith bullets.

The second type of roll crimp has the lip of the case mouth forced inwards into a cannelure or groove in the bullet.

Three others types are:- taper crimps, folded crimps and bevel crimps...

A taper crimp is when the lip of the case mouth is merely compressed against a bullet's sides.

Bevel crimps occur on flat nose or semi wadcutters where the metal from the lip of the mouth is folded over the flange rather than rolled completely over.

Folded crimps are rare if used with a bullet, but are commonly used on blank and grenade launcher rounds. They are also used with shot loadings in metallic cases.

There is also a crimp type that is sometimes used on military ammunition. There are two distinct forms of this crimp, in both cases the bullet is seated to a greater depth so that the cannelure (if present) is well below the lip of the case mouth. In one case the crimping dies (usually four) form a ring where the cannelure in the bullet is, forcing case metal into the cannelure. In the other style the dies are slightly oblique to the axis of the cartridge (at a similar angle to the rifling in the barrel) and they press case metal into shallow depressions that are formed in the bullet jacket by the crimping action. This heavy crimping serves two purposes, it ensures that the bullet remains in place during rough handling and it enables the initial pressure to rise to a sufficient level for reliable and consistent firing.

Roll and bevel crimps are commonly employed in revolvers due to high recoil that could dislodge a loose fitting bullet and jam the action. Automatics have less recoil and thus can get away with the less positive grip of the taper crimp.

The head of the case has several features.
The flat base has a central area where the primer is fitted, around this there is an annular groove which is formed due to the curvature of the outer edge of the primer and the lead in curvature of the primer recess or primer pocket. There is sometimes a second crimp groove outside of this, that is intended to increase primer retention. The two annular grooves are often confused with each other. The outer margins of the base are usually impressed with various markings indicating manufacturer, batch, calibre and year of manufacture. These markings are collectively known as the headstamp.

There are six types of head which are:- rimmed, rimless, rebated, belted, belted rimless, rebated belted rimless.

A rimmed case has a flange around the head that is larger than the case body. Often used on a cartridge designed for revolvers or older rifles.

A rimless cartridge case has a "V" shaped groove around it's head and is the same diameter as the back end of the case. Often employed in self loading rifles and light machine guns.

A rebated rim cartridge is grooved in the same fashion as the rimless, but the grooved portion has a smaller diameter than the rest of the cartridge. Like rimless cartridges, these cartridges are mainly designed for automatic weapons.

Belted heads have a narrow raised portion just in front of where a rim would be if it had one, this thickened belt has been used in some big game calibres as a strengthening measure and in some pistols designed for use with speed loaders.

Belted rimless is a combination of belted and rimless and is common on magnum calibres, where it helps withstand the stresses between base and case.

Rebated belted rimless is likewise a combination of belted and rebated rimless.

The primer pocket is a cylindrical recess in the centre of the base of the case. This is where the primer is inserted. The primer is sometimes retained by a ring shaped indentation that displaces metal into the annular groove. This is also known as a hard crimped primer. Identification paint is sometimes applied and then wiped off leaving coloured rings in this crimp groove and the annular ring.

Flash holes (1, 2 or 3 in number) are drilled in the base of the primer pocket. 1, 2 or 3 occur in Berdan primed cases, Boxer versions usually have just one large centre hole, but I have seen examples that had a central hole and two "D" shaped angled slots.

This page deals with ammunition that has a primer and primer pocket located in the center of its head and is thus called centrefire ammunition. There is another method that can be used at low service pressures... This utilises a case that is made from sheet brass or steel that is drawn and swaged into shape. The shape incorporates a rim and there is an annular space within this rim that is filled with a priming compound that is initially liquid and flows into the rim then the compound dries and sets. The hammer or firing pin strikes the base of the case at the edge of this rim and the system is known as rimfire. Mainly .22 calibre, but also used on some .44 calibre and .41 calibre cowboy era revolvers. Cartridge operated nail guns and captive bolt humane killers also use the rimfire system. The Number 3 garden gun and a .22 dust shot cartridge are the only shotgun cartridges to use rimfire ignition.

The physical dimensions, the features of the case, the cartridge or rifle designer's name and the calibre it was designed for plus the calibre it actually uses (if it is a necked down version) are used to designate and identify a cartridge.

Propellant Powder or Gun, rifle, and pistol Powder form the powder charge which fills most of the volume of the case. This powder does not detonate when ignited, but burns very rapidly and progressively, producing hot gases that cause high pressure in the case body. The high pressure gas pushes the bullet from the case mouth into the forcing cone, where it engages the rifling and progresses down the barrel of the gun. The pressure inside of the brass case, coupled with the intense heat, swells the case walls into close contact with the inner surface of the chamber, thus sealing the breech.

There are many different compositions of powders. They are sometimes described by the shape of their grains. There are, ball powders, disc powders, tubular powders, rod forms, extruded flake and flake powders. I have heard of a powder that was intended for large calibre revolvers that had a doughnut shape to the individual grains.

There are two main divisions within powders black powders and nitro powders. The nitro powders then fall into two types, single based and double based (dibasic).

Black powder is for older loads in old calibres and some blank cartridges.

Single base nitro cellulose powders are considered by some to be less stable at high ambient temperatures.

Dibasic powders contain nitro cellulose grains that have absorbed nitro glycerine, the result being a powder that is more stable than either of its constituents.

The primer sits in the primer pocket of the case head. It is composed of a soft copper, bronze or brass cup, a compound that will detonate due to percussion and sometimes an anvil to oppose the striker blow. When the primer is struck by a firing pin, the priming compound detonates sending an intense flame through the flash holes into the powder located inside the cartridge case. This flame then ignites many individual powder grains initiating the rapid burn which produces the hot, expanding gases that force a bullet along the barrel.

There are two major types of primer used today... the Berdan primer and the Boxer primer.

Boxer primers are preferred in America, where they are considered to be more easily reloaded.

Berdan primers are simpler, cheaper and more reliable. These find favour in The UK and Europe where reloading does not rely on pushing out the spent primer with a pin, but uses a pulse of hydraulic pressure to expel the old cap.

The bullet is the projectile and the sealing method for the front of the case. Bullets may be cast from lead or lead alloy or have a lead core with a gilding metal (cupro nickel) jacket. The jacket may completely cover the bullet or only partially cover it. A third form exists that is a combination of the two, whereby a solid one piece bullet is cast or swaged from an alloy material that has physical properties similar to the overall properties of a jacketed bullet.

There are bullets under development that have moulded plastic jackets (as opposed to loose fitting sabots) or are made by injection moulding a plastic compound that has an admixture of heavy metal powder to increase the density. There is potential and scope here for a plastic moulded bullet with tungsten powder density improver that has a jacket or driving sleeve moulded from a plastic with good lubricating properties.

Bullets are usually streamlined in shape to reduce air resistance and increase target penetration. There are exceptions and there are flat faced and various other forms of blunt nosed bullet designs.

Some bullets contain inclusions of tungsten alloy or hardened steel that increase the sectional density and/or provide armour piercing characteristics.

Bullet noses may have axial holes, hollow points or cavities to increase expansion on impact, various aluminium or plastic tip inserts may be used to modify the expansion.

Cast bullets often have several prominent grooves around the parallel portion. The grooves are used to retain large quantities of bullet lubricating compound that are needed to stop friction welding of lead particles to the internal surface of the barrel. These grooves also provide spaces for the prominent ridges to be deformed or swaged into by the rifling grooves. Jacketed bullets often have one (or more) rings of toothed indentations known as a cannelure, the main reason for this is bullet retention as there is no need to lubricate the jacketed bullets, indeed such lubrication would give rise to a form of barrel damage known as ring bulging.

Bullet bases can be flat or recessed and some use a tapered boat tail shape. Some bases are entirely covered by jacket metal and others have exposed lead. Cast bullets are sometimes (mainly) gas checked whereby a shallow cup of gilding metal is added to the base either during casting or pressed in position after casting. On tracer or incendiary bullets there is a central match compound that ignites the incendiary or tracer compound within the bullet from the flame of combustion of the main propellant charge.

Bullets come in many shapes and styles, each of which was generated with a particular purpose in mind. The multiplicity of shapes increases as each generation adds it's own fads and fancies to the melting pot. The different bullet shapes a headstamp variations have become a collecting cult in their own right.

8x68S

The 8x68S rifle cartridge (the S stands for Spitz and also means it is intended for 8.2 mm (.323 in) groove diameter spitzer bullets) and its necked down sister cartridge the 6,5x68 (no S required) were developed in the 1930-ties by Mr. Schüler as magnum hunting cartridges that would just fit and function in standard sized Mauser 98 bolt action rifles. This is one of the early examples where a de novo rifle cartridge (the 8x68S and 6,5x68 have no other cartridge as parent case) was developed by a gunsmith to fit a specific popular and widespread type of rifle.

History

The German ammunition manufacturer RWS (Rheinisch-Westfälischen Sprengstoff factories) introduced both cartridges commercially in the spring of 1939. Standard military 7.92x57 mm Mauser 98(k) rifles have to be adapted by a competent gunsmith to function properly with these magnum cartridges since they are longer and the cases have a larger diameter then 7.92x57 mm Mauser cartridges. The 7.92x57 mm Mauser cartridge is also known as the 8 mm Mauser or in Germany as the 8x57 IS (IS stands for Infantrie Spitz). In adapted standard military Mauser 98k) rifles the large 8x68S cartridges are however praised for very smooth and reliable feeding.

The widespread availability of standard size Mauser 98 rifles and the fact that the .375 H&H Magnum cartridge and its necked down version the .300 H&H Magnum with approximately 72.4 mm case length were to long to fit in standard sized Mauser 98 bolt action rifles made the shorter 8x68S an interesting chambering option.

World War 2 spoiled the commercial introduction and spread of the 8x68S amongst German hunters. The cartridge became due to its high performance and flat trajectory popular after Word War 2 when German hunters were allowed again the own and hunt with full bore rifles. The 8x68S performance also made that hunters who had problems with handling magnum cartridge recoil stepped down to less powerful but for German conditions adequate medium cartridges like the 7.92x57 mm Mauser, 7x64 (Brenneke) or .30-06 Springfield (also know as the 7.62x63 in metric countries). Recoil sensitive shooters can fit an efficient muzzle brake to significantly reduce the amount of recoil. With the help of a muzzle brake the 8x68S recoil is reduced to tolerable levels.

Cartridge Drawing and Dimensions

Extremely thick brass results in 'only' 5.584 ml (86.0 grains) H2O cartridge case capacity for the 8x68S. A rare feature of this German rimless bottlenecked centerfire cartridge design is that it has a slightly rebated rim (P1-R1 = 0.3 mm). A sign of the era in which the 8x68S was developed are the gently sloped shoulders to promote reliable case feeding and extraction.

8x68S maximum cartridge dimensions. All sizes in millimeters (mm). Americans would define the shoulder angle at alpha/2 ≈ 14.53 degrees.

According to the official with CIP (Commission Internationale Permanente Pour L'Epreuve Des Armes A Feu Portative) guidelines the 8x68S case can handle up to 440 MPa (63,817 psi) piezo pressure. In CIP regulated countries every rifle cartridge combo has to be proofed at 130% of this maximum CIP pressure to certify for sale to consumers.

The American .325 WSM cartridge introduced in 2005 is probably the closest ballistic twin of the 8x68S. The .325 WSM is considerably shorter and fatter and has a more radical rebated rim (P1-R1 = 0.51 mm), much steeper shoulder angle (70 degrees / 35 degrees for Americans) and a shorter neck (7.82 mm). This makes the 8x68S case with its 9.11 mm long neck better suited for loading long heavier bullets and due to its sleeker exterior shape bound to cycle more reliable in bolt action rifles in extreme situations.

The 8x68S in Field Use

German big game hunters often use 8x68S rifles in Africa for hunting plains game, where American hunters would choose one of the .30 or .338 magnum cartridges. The 8x68S as a pure civil cartridge can be used in countries which ban civil use of former or current military ammunition.

Since there are not much factory loads available (RWS offers 2 factory loads) and due to its good field reputation and efficiency, the 8x68S is often used by reloaders. They have used this cartridge extensively to create powerful loads by handloading. Whilst staying within the 440 MPa CIP limit a 8x68S rifle with a 650 mm (25.59 in) long barrel and appropriate modern gunpowder (Vihtavuori N560) can be handloaded to propel a 12.96 gram (200 gr) 8 mm bullet like the Sierra MatchKing to a muzzle velocity of 927 m/s (3042 fps).

Maximum muzzle velocity comparison in % of the probably most proliferated European and American 8 mm rifle cartridges out of 650 mm (25.59 in) long barrels loaded with relatively light to heavy 8 mm bullets to their CIP or SAAMI sanctioned maximum pressures.

Bullet weight (grain)	8.23 gram (127 gr)	9.72 gram (150 gr)	11.34 gram (175 gr)	12.96 gram (200 gr)	14.26 gram (220 gr)	Case capacity (%)
7.92x57 mm Mauser (8x57 IS)	100.00	100.00	100.00	100.00	100.00	100.00
325 WSM	108.67	109.12	109.01	109.30	111.14	131.73
8x68S	108.38	108.50	108.68	110.49	112.27	136.49
8 mm Rem. Mag.	111.89	112.33	114.46	115.26	116.02	157.13

This comparison is not totally objective since the 8 mm Remington Magnum and 325 WSM operate at 448.16 MPa (65000 psi), the 8x68S at 440 MPa (58740 psi) and the 7.92x57 mm Mauser at 390 MPa (56564 psi). Higher pressure results in higher muzzle velocities.

The 8x68S has a good long range accuracy reputation i.e. it is not hard to develop or find loads that will shoot 1 MoA or better out of decent standard mass produced rifles. Factory 8x68S rifles often have a 650 mm or 26 in barrel with a 280 mm (1 in 11 in) twist rate, which works well in daily life. This twist rate was chosen since the bullet jackets used in the 1930-ties were not strong enough to cope with the forces generated by the magnum muzzle velocities of the 8x68S. The 240 mm (1 in 9.45 in) twist rate normally fond in the 7.92x57 mm Mauser makes the 8x68S combined with modern bullets with jackets designed for magnum cartridges an awesome long range cartridge.

Reloaders use the 8x68S as a Jack of all trades cartridge on all European game from fox, roe deer and chamois upwards to the big European game like red deer, moose and brown bear. These people realized that bullets with different characteristics can be utilized to produce varying effects on game. They also realized that from 8 mm caliber upwards the rise of sectional density and penetrating capability of practical spin stabilized rifle bullets (bullets up to 5 calibers in length) tends to flatten out.

This means that loaded with light, short and soft nosed 8 mm bullets the 8x68S can be used on remarkable small game. Loaded with heavy, long and hard (solid copper) bullets the 8x68S offers enough speed derived power to penetrate heavy and dangerous game. In the Central African Republic, where there are no ammunition limits for hunting Big Five game, the 8x68S is even used successfully for hunting elephant.

The 8x68S as Parental Case

Because the 8x68S offers an exceptional sturdy pressure resistant cartridge case that can relatively easily be reloaded with primers, powder and bullets and hence be reused several times. It has become quite popular amongst wildcatters to create wildcats like the .25x68, .27x68, 7x68, .30x68, .338x68, .375x68 or .416x68. Improved or blown out 68mm cartridge designs are reported to bridge the performance gap to the 8 mm Remington Magnum which has about 14% more case capacity then the standard 8x68S.

Since wildcats are not governed by CIP rules or its America equivalent SAAMI they can capitalize the achievable high operating pressures. It is often reported that modern 68mm RWS brass can tolerate up to 500 MPa (72,519 psi) piezo pressure. Examples of 68mm wildcats are the relatively well know American 7 mm and .30 caliber Boo Boo and 7 mm and .30 HV wildcats. The Boo Boo wildcats were developed for long range target shooting were participants usually handload their ammunition. Several 1,000 yard shooting competitions have been won with Boo Boo wildcats.

A wildcat from Europe that uses the 8x68S as its parent case is the .30 Kovacs. It was designed in 1996 by Stefan Kovács, Austria-7041 Wulkaprodersdorf. The .30 Kovacs has much more powder-room (longer L2, wider P2, 40 degree Ackley-shoulder) then its parental case. It falls powder-room-wise between the .300 Winchester Magnum and .300 Wby. Mag but has energy and velocity falling between .300 Weatherby Magnum and the .300 Remington Ultra Magnum. This wildcat cartridge will be fitted only by Büchsenmachermeister Egon Kriebernegg, AUSTRIA, 7000 Eisenstadt (see web-site) contact: skbullets@hotmail.com or look at www.kriebernegg.com.

Reloader's Language
Reloading has its own "language". Here are some words to familiarize yourself with. See the Speer Reloading Manual for more reloading information.

BELL
To flare a case mouth to receive a bullet easily.

BULLET
A piece of metal formed into a projectile. Available in a variety of shapes and weights.

BULLET SWAGING
The forming of a bullet using pressure in a die instead of casting molten lead in a mould.

CALIBER
The approximate diameter of a bullet or gun bore.

CARTRIDGE
A completely loaded, ready-to-fire round of ammunition.

CASE
A metal cylindrical container which holds the primer, powder and bullet. Also called brass.

CASE FORMING
To form cases of one caliber into a different caliber.

CHAMFER
To bevel the inside of a case mouth. The bevel allows bullets to start into the case mouth without crushing the case.

CHRONOGRAPH
An instrument used to measure the velocity of a bullet.

COMPONENTS
The parts that make up a cartridge. The case, primer, powder and bullet.

CRIMP
To bend inward the mouth of a case to grip the bullet. Used only with bullets having a cannelure or crimping groove.

DEBURR
To remove the small metal burrs from inside and outside of a case mouth.

DECAPPING
Removal of the spent primer from a fired case.

DECAPPING PIN
The slim needle-like rod in the sizer die which pushes out the spent primer.

EXPANDER
The part of a die that expands the case mouth to receive the bullet.

FLASH HOLE
The hole through which the primer ignites the powder charge in a case.

HANDLOADING
Another term for reloading.

HANGFIRE
Slang term for any detectable delay in cartridge ignition.

IGNITION
The action of setting a powder charge on fire.

JACKET
The cover or "skin" of a bullet.

MISFIRE
The failure of a cartridge to fire after the firing pin strikes the primer.

NECK
That portion of a case which grips the bullet. In a bottlenecked case, that portion of the case in front of the shoulder.

NECK SIZER DIE
A die used to resize only the neck portion of the fired case back to approximately its original dimensions.

POWDER
The substance that ignites in the cartridge and propels the bullet.

POWDER CHARGE
The amount of powder loaded into a case.

PRIMER
The small cap containing a detonating mixture used to ignite the powder charge in the case.

PRIMER POCKET
The cavity in the bottom of a case into which the primer is seated.

PRIMER POCKET SWAGING
The "smoothing out" of the crimped primer pocket found in military cases.

PRIMING
Installing a new primer into a case.

RAM
The steel rod running through the center of the press that holds the shell holder and drives the case into the die.

RELOADING PRESS
The tool which performs the major tasks of reloading.

RESIZE
To restore a fired case to approximately its original size.

ROUND
A military term for one complete cartridge.

SEATER DIE
The die that seats the bullet into the mouth of the powder charged and primed case.

SEATING DEPTH
The depth to which a bullet is seated in the case mouth.

SHELL HOLDER
The part that holds the case in proper alignment while the case is being run into the die.

SIZER DIE
A die used to resize a fired case back to approximately its original dimensions.

SPENT PRIMER
A primer that has been fired.

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The 8x68S in Field Use

The 8x68S as Parental Case




	The photographs above shows an ammunition measuring and adjustment device manufactured by BERSIN . This device diagnoses and eliminates errors in the longitudinal axis in rifle ammunition i.e. concentricity flaws. The photograph on the left shows a similar device manufactured by SINCLAIR.


MEASURING BULLET VELOCITY


The above photographs show the CED Millennium Chronograph, with its advanced technology, functional design and unique features, and it works at not an outrageous price.