ERIC'S OPEN SIGHTS PAGE
Welcome to my Open sights Page
where you will find info about
Open sights and how to maintain them
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The usual sight options for hunting rifles are open iron sights (from buckhorn to express), aperture sights (tang, receiver, peep or ghost ring), and optical (telescopic) sights. Open iron sights of one sort or another are supplied on many rifles, the other types must usually be purchased separately and installed by the rifle owner.
Open sights
Open sights consist of a rear sight and a front sight. The rear sight is typically an upright, transversely mounted metal blade into which has been cut a "V," "U," or square shaped notch. It is usually secured in a dovetail slot or screwed onto the rifle barrel toward the breech end so that the notch lines up with the shooter's eye. The front sight takes the form of a vertical blade or post dovetailed, screwed, or sweated onto the muzzle end of the barrel, often on some sort of ramp. Sometimes it is protected by a removable metal hood. The idea is to center the front post in the rear notch, keeping the top of the front sight level with the top of the rear sight (as seen by the shooter's eye). When correctly zeroed, the bullet should hit right at the top of the front post.
A gold, ivory, or red coloured bead is often affixed to the face of the front sight to enhance visibility in dim light.
One problem with all front sight beads is that they tend to shoot away from the light. Their curved surface reflects a highlight in the direction of the sun, which becomes a false aiming point. This is one reason why a non-reflective black, flat-topped front sight with an undercut face is the most accurate type of front sight. Unfortunately, it is also the least visible in dim light.
The most common type of open rear sight, often supplied on factory produced rifles, consists of a simple, flat-topped, "U" notch rear sight dovetailed onto the barrel. These sights are usually adjusted for elevation by means of a stepped slider and for windage by drifting them laterally in their dovetail mounting notch.
Other types of reasonably common open rear sights include the express sight with its shallow "V" (more about which later), the buckhorn, and the semi-buckhorn. The buckhorn type looks like a standard rear sight with a small "V" notch and large ears or wings sweeping up from each side of the rear sight, which nearly meet directly over the center of the sight. The effect is something like the upper half of a ghost ring grafted onto a standard open rear sight mounted on the barrel, and cut away at the 12 o'clock position.
On the semi-buckhorn rear sight the sweeping ears of the buckhorn sight are reduced to a bulge on each side of the central notch. The semi-buckhorn rear sight, as seen from behind by the shooter, takes the form of a wide, shallow "U" with a much smaller and more precise "U" or "V" shaped aiming notch at its center. The standard Winchester Model 94 and Marlin 336 rifles are supplied with semi-buckhorn rear sights.
There are, of course, many variations and some open rear sights are screw adjustable for windage and elevation. Remington and Ruger rifles, for example, often come with screw adjustable rear sights. The Williams Company has a rather complete line of fully adjustable open rear sights. Like the other types, open iron sights have advantages and drawbacks. Among the advantages are the following.
 | Simple. There isn't much, mechanically, to go wrong with most open sights, and the simple type supplied with many factory built rifles are practically immune to the effects of recoil. |
| Light weight. Open sights are probably the lightest of all sights and have less impact on the balance and handling of the rifle than other types. |
| Durable. Because they are usually low in profile open rear sights are less likely to get knocked about than other types; however, most front sights are more fragile than one would think and can fairly easily be knocked out of alignment. This is led to the demise of the famous outlaw/rifleman Harry Tracy in his last gunfight. It is also why military rifles usually have heavy wings on either side of the front sight blade for protection. |
| Nearly impervious to the weather. Neither rain nor sleet nor snow usually has much affect on open sights. |
| Cheap. They are often supplied with the rifle. Since rifle manufacturers know that most shooters are going to ignore or remove the supplied open sights anyway, they are not willing to spend a lot of money on them. |
Then there are the following disadvantages.
| Imprecise. The ordinary open sight is the least accurate of the three main types of sights. The square notch (Partridge type) of open rear sight combined with a square faced front blade is the most accurate type of open sight. |
| Difficult or impossible to adjust accurately. There are micro-adjustable open sights, but for the cost of these the shooter could probably buy an optically superior aperture sight. The type of open rear sight supplied with most factory made rifles has crude adjustments. This means that factory supplied open sights usually require the greatest expenditure of ammunition to sight-in. Often the cost of the ammunition wasted attempting to precisely zero factory supplied open sights would have paid for a receiver or optical sight. |
| Slow. Contrary to legend, the standard type of open sights are the slowest of all sights to line up for a shot. The express sight with its broad, shallow "V" and big front bead is a fast sight, and the fastest of all open iron sights. The "U" or deep "V" or square notch (Partridge type) of open rear sight is slow, and the buckhorn rear sight, with its tall wings on each side of a small notch, which serve only to blot out much of the view over the sight, is the slowest of all. |
| Limited field of view. The naked eye has a huge field of view, of course, but the rear open sight and front bead combine to obscure most of the lower half of the target and the surrounding view below the top edge of the rear sight. The buckhorn style of rear sight, with its useless ears, is the worst offender, blocking out about two thirds of the target and surrounding area. The least offensive type is the express rear sight. |
| Optically inferior. By which I mean that open sights are the most difficult type of sight for the human eye to use. They require the eye to focus simultaneously on three things at different distances: the rear sight, the front sight, and the target. The human eye has a lot of depth of field, but not that much; this is literally an impossible task. Young shooters with a lot of visual accommodation can make a fair stab at it; farsighted, middle aged and older shooters simply cannot. |
For all of these reasons, simple open sights of the type supplied with most factory rifles are the least versatile and least accurate of all commonly encountered rifle sights. In the hands of an expert they might allow a 200 yard shot at a medium size big game animal. In the hands of an average marksman and deer hunter their use should be limited to about 100 yards. They are best used as emergency sights only, in case the primary sighting system is somehow disabled. Better yet, of course, is a spare rifle with decent sights.
The express sight is one type of open sight that is still useful. It consists of a very shallow, wide "V" (usually with a white line marking the bottom of the "V") combined with a large, low, gold or white front bead. The "B" blade for the Williams WGOS sight is a good example of an express rear sight.
The express is a specialized sight used for hunting dangerous game, and is commonly fitted to double-barreled and other "Express" or "African" rifles. This was developed by the British, who have a penchant for hunting dangerous African and Asian game, but not for being eaten or trampled. Its purpose is to allow a fairly well aimed shot over moderate ranges when there was time for careful sighting, and to allow the rifle to be pointed like a shotgun to stop the charge of a dangerous animal at very short range when there wasn't time for aiming. In the latter capacity the sights are ignored, and its utility is merely that it interferes less than other sights with pointing the rifle.
Aperture sights
Like open sights, aperture sights are iron sights. They are also called "peep" sights and more recently "ghost ring" sights. They use a front sight similar or identical to open sights, but the rear sight is simply a ring mounted close to the shooter's eye. Aperture sights can be variously mounted on the tang, cocking piece or receiver, depending on the type of rifle.
The shooter looks (peeps) through the ring, attempting to focus only on the front sight and target. (Still impossible, but less so than the three focus points required by open sights.) The eye automatically centers itself in the rear aperture, which is seen only as an out of focus blur (or ghostly ring).
Do not use a target disc (an insert with a tiny hole that screws into the rear aperture sight) in the field. These increase the eye's depth of field for target shooting, but restrict the light reaching the eye and the field of view. Target discs can be unscrewed from receiver sights that are supplied with them.
The closer the aperture sight is to the eye, the faster it is to use. The old fashioned tang mounted sights sometimes seen on lever action and single shot rifles are probably the fastest of all iron sights. They also provide the longest sighting radius, which is a factor in potential accuracy. But they should never be used on powerful rifles, where the recoil and the consequent muzzle jump can drive them into the eye. The best compromise is probably to mount an aperture sight on the rifle's receiver.
Because they are optically superior to open sights, aperture sights are more accurate. A good shot should shoot 100 yard groups perhaps 33% smaller with an aperture sight than he or she could with factory open sights. Aperture sights also obscure much less of the target and the surrounding area than open sights, and are faster to acquire. Most aperture sight designs allow accurate, repeatable, windage and elevation adjustments. Receiver mounted aperture sights are the traditional sights used on military rifles, and probably the best all-around type of iron sights for the hunter. Many, many years ago, before the introduction of practical and reasonably priced telescopic sights.