Letter S

The Definition of Shell

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Shell

An empty ammunition case.


19 Other Firearms Definitions You Need To Know


Underbolts

A sliding bar, running longitudinally through the watertable of a break-open side-by-side gun's action, with openings through which the lumps of the barrels pass when the gun is closed. Under spring tension, this bar moves forward when the opening control is released and its two locking surfaces engage complementary slots (bites) in the rear of the two barrel lumps. Originally operated by a hinged tab in front of the trigger guard. Now invariably operated by a cam from Scott's [toplever] spindle. Most modern side-by-side guns lock closed in this manner.

Blowback

A semi-automatic firearm whose breechblock and barrel are not mechanically locked together when fired. In such case the breechblock immediately begins to separate from the barrel upon firing. Blowback is used in comparatively low powered weapons, in which inertia of the breechblock, and cartridge wall adhesion against the chamber, are sufficient enough to retard opening until breech gas pressures have fallen to a safe level.

Bull Barrel

Bull barrels are barrels that are not tapered at all. These very heavy barrels, designed for extreme accuracy, are usually seen on target rifles.

Lockplate

A metal plate on which the firing mechanism is mounted on percussion and earlier firearms.

Trigger Slap

An uncomfortable sensation caused by the trigger springing back into the shooter's trigger finger while firing.

Trigger Guard

Usually a circular or oval band of metal, horn or plastic that goes around the trigger to provide both protection and safety in shooting circumstances. The shooter's finger should never be within the trigger guard unless the sights are on target and the shooter has made the decision to fire.

Ejection Rod

The sliding metal dowel located at the muzzle end of a revolver cylinder. After firing, the shooter opens the cylinder and depresses the front end of the ejection rod, which forces the empty cases out of the cylinder.

Night Sights

A type of iron sights that glow or shine in the dark, intended for use in low light conditions. Some night sights consist of tiny tubes of tritium, while others use a phosphorus paint.

Mauser Safety

A small lever mounted to the cocking piece of a Mauser 98 action (and its copies such as the Springfield 1903), rotating on a longitudinal axis from left (Fire), up to the top (Safe, but allowing bolt movement), and over to the right (Bolt and firing pin locked Safe). While commendable for locking the firing pin instead of just the trigger, its up-and-over arc of operation requires a scope to be mounted awkwardly high. Paul Mauser is not to be blamed; when his safety was developed, telescopic sights were in such infancy as not to be worthy of mainstream consideration.

Eye Dominance

Although we have two eyes for depth perception and for spare parts, there is a natural tendency for one eye (the master eye) to take precedence over the other, regardless of the relative visual acuity of each eye. It is a fortunate condition when the eye on the side of the shoulder where one is comfortable mounting a gun is also the dominant eye.
To test for eye dominance:

Pick out a small object several feet away. With both eyes open, center your right index finger vertically over the object. Close your right eye. If your finger appears to jump to the right, you are right eye dominant. Then open your right eye and close your left eye. If your finger remains in position in front of the object, you have confirmed your right eye dominance. Alternatively, if in the above test, upon closing your right eye your finger remains in position covering the object, you are left eye dominant. If you close your left eye instead and your finger appears to jump to the left you have confirmed your left eye dominance.
Eye dominance problems can be treated with
1. A severely-cast, crossover stock to bring the dominant eye in line with the gun's line of sight, 2. A patch over the dominant eye, or just a small piece of frosty Scotch tape on shooting glasses intercepting the dominant eye's line of sight, 3. Fully or partially closing the dominant eye, or 4. Learning to shoot from the dominant-eye shoulder.
While less convenient, methods that retain the use of both eyes better preserve the ability to perceive depth in three-dimensional space, a great benefit in wingshooting.

Zeroing

The act of setting up a telescopic or other sighting system so that the point of impact of a bullet matches the sights at a specified distance.

Penetration

The distance travelled by a projectile from the point where it strikes the target to the point where it stops.

Safe

A firearm is said to be on safe when its safety is engaged and off safe when it is ready to fire.

Magna

Smith & Wesson term for a revolver grip design introduced in the 1930s where the top of the grip extends higher than it had in earlier configurations, to provide a more comfortable hold.

Mag

Slang word for Magazine.

Muzzle Flash

A muzzle flash is the visible light of a muzzle blast, which expels high temperature, high pressure gases from the muzzle of a firearm. The blast and flash are caused by the combustion products of the gunpowder, and any remaining unburned powder, mixing with the ambient air. The size and shape of the muzzle flash is dependent on the type of ammunition being used and the individual characteristics of firearm and any devices attached to the muzzle (such as a muzzle brake or flash suppressor)

Printing

Is when the outline of the concealed handgun may be discerned through the outer clothing.

AK

AK stands for Avtomat Kalashnikova (Kalashnikov rifle when translated into English). When someone says "an AK" they are usually referring to the AK-47 rifle which was originally designed in Russia by Mikhail Kalashnikov.

Annulus

A tiny circular recess at the base of a cartridge case surrounding the primer pocket. Recoil from fired cartridges invariably impress a discernable ring on the breech or bolt face of a firearm, providing some evidence of the amount of use it has seen.