Letter T

The Definition of Thumb Safety

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Thumb Safety

An external, manual safety which is typically disengaged with the firing-hand thumb.


19 Other Firearms Definitions You Need To Know


Overbore Ammunition

Small caliber bullets being used in large cases. E.g. .22 bullet in a .45 acp case.

Off Hand

To shoot while standing and without bracing against anything. Sometimes it can also mean to shoot with your non-dominant hand.

Submachine Gun

A fully automatic firearm that fires pistol ammunition.

Lede

The bevelled portion of the rifling at the rear end of the barrel (and the forward portion of the chamber) where the bullet first engages the lands.

Pattern

A shotgun term which refers to the manner in which the pellets spread out as they exit the gun. "The pattern" refers to the overall shape of the entire set. A tight pattern is one in which the pellets are closely grouped when they land on target. A loose pattern is one in which the pellets are widely spread.

Twilight Sight

A rifle front sight with a extra-large, folding bead. Typically, in addition to the normal fine bead (which allows for more precision) the larger bead, while at a cost of potential accuracy, is more readily acquired in marginal light. Also called a Gloaming sight

Cordite

A family of smokeless propellants developed and produced in the United Kingdom from 1889 to replace gunpowder as a military propellant. Like gunpowder, cordite is classified as a low explosive because of its slow burning rates and consequently low brisance. The hot gases produced by burning gunpowder or cordite generate sufficient pressure to propel a bullet or shell to its target, but not enough to destroy the barrel of the firearm, or gun.

Percussion Cap

A small metal explosive-filled cup which is placed over the nipple of a percussion firearm. As the cap is struck by the hammer, it explodes and sends a flame through the flashhole in the nipple to the main powder charge.

Slide Catch

Sometimes also known as a slide lock, slide release or slide lever. On a semi-autmatic gun, the lever or catch that holds the slide open (after the last round is fired or when racking an empty gun). Typically they are located on the left side of the frame about mide barrel. Some of the newer semi-automatic pistols have an internal slide lock. Even though on pistols with an external slide catch, you can push down on the lever to release the slide, it should never be used in such a manner. The proper way to release the slide is to rack the slide.

Short Trigger

A trigger that doesn't have to travel very far before it reaches the break. In a 1911 semi-auto pistol, a short trigger is a different part than a long trigger, and (in addition to providing less motion) it features a shorter reach which may be of benefit to a small-handed shooter.

Snap Caps

Dummy cartridges with spring-loaded "primers" used to test the mechanical functioning of a firearm, particularly the trigger pulls, hammer-fall and ejector-timing of a break-open gun. It is not advisable to dry-fire a break-open gun on an empty chamber. Hardened steel parts can shatter without the soft brass primer to act as a shock absorber. Snap caps cushion the blow of the hammer and firing-pin when the use of a live cartridge would be impractical.

Button Rifling

Rifling that is formed by pulling a die made with reverse image of the rifling (the 'button') down the pre-drilled bore of a firearm barrel.

Cable Lock

A cable with a padlock at the end. It is threaded through the action of the firearm rendering the gun safe and useless until the lock is removed.

Collateral Damage

Damage that is unintended or incidental to the intended outcome.

Pigeon Gun

A double-barrel shotgun, with relatively tight choke boring and a relatively high-combed stock used for shooting live pigeons (euphemistically known as flyers) which normally rise when released. To better absorb recoil, a pigeon gun is normally heavier than a field gun as one shoots heavy loads and walks only a little. Because of the inevitable expense of this shooting discipline, pigeon guns are often built to a high standard of quality and reliability in deluxe grades with highly figured walnut stocks and fine engraving.

Cylindro Conoidal Bullet

A hollow base bullet, shaped so that, when fired, the bullet will expand and seal the bore. It was invented by Captain John Norton of the British 34th Regiment in 1832, after he examined the blow pipe arrows used by the natives in India and found that their base was formed of elastic locus pith, which by its expansion against the inner surface of the blow pipe prevented the escape of air past it.

Shell

An empty ammunition case.

Muzzle Brake

An attachment to or integral part of the barrel that redirects some of the pressurized gas that propelled the bullet out the muzzle to the sides and possibly rearwards from the direction of the bullet travel. This reduces the recoil of the firearm.

Fouling Shot

A fouling shot is a shot fired through a clean bore, intended to leave some residue of firing and prepare the bore for more consistent performance in subsequent shots. The first shot through a clean bore will behave differently from subsequent shots through a bore with traces of powder residue, resulting in a different point of impact.