Letter P

The Definition of Percussion Cap

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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.

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.


18 Other Firearms Definitions You Need To Know


Quadrail

Sometimes spelled Quad Rail. First conceived and sold by Knights Armament Company in the mid 90s when Reed Knight saw soldiers duct taping flashlights to their handguards in news footage of Panama, the quad rail has become almost a standard item found on most military rifles. Quad rails allow easy attachment of accessories which aid tactical shooters, such as lights, infrared lasers, foregrips, sling attachment points, and secondary sighting systems. However, nowadays, any full length forearms on an AR, with or without rails may also be refered to as a Quadrail.

Lock Speed

The same as Lock Time

Follow Through

Holding the trigger to the rear after the shot has fired, until the sights are back on target, at which time the trigger is released.

Stock

The back part of a rifle or shotgun, excluding the receiver.

Hammerless

A firearm with a coil-spring-actuated firing pin, or with its hammer enclosed inside the action body; i.e.. no externally visible hammer.

Drop-Box Magazine

An extra-deep magazine typical of large calibre rifles for dangerous game. The line of the underside of the wrist does not carry straight forward as with ordinary rifles. Rather the rear of the magazine aligns more towards the center of the forward edge of the triggerguard, typically allowing at least one extra cartridge to be carried.

Line Of Bore

An imaginary straight line through the centre of the bore of a firearm extending to infinity.

Cast Off

An offset of a gun stock to the right, so that the line of sight aligns comfortably with the right eye while the butt of the stock rests comfortably on the right shoulder. Almost all right-handed shooters benefit from a little castoff and most custom built guns are made this way. The only question is how much. The castoff of a gun is about right when, with the gun comfortably mounted, the front bead lines up with the center of the standing breech.
A stock offset to the left, for shooting from the left shoulder is said to be

DA

Abbreviation for Double Action

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.

Tunnel Claw Mount

A claw [scope] mount with openings through which a shooter can use a rifle's iron sights without removing the scope.

Overbore Capacity

Is that combination of caliber, barrel length, bullet weight, and case volume which does not allow the complete burning of the charge of ballistically correct powder within the volume of case and barrel.

Pistol Grip

The handle on a pistol. Can also refer to a vertical grip behind the trigger on a rifle.

Naked Bullet

A bullet not covered by a metal jacket or patch.

Muzzle Energy

The power of a projectile or a load of shot at the point that it exits the muzzle of a firearm, normally expressed in foot-pounds.

Rate of Fire

The frequency at which a firearm can fire its projectiles.

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.

Doll's Head

A rib extension on a break-open gun, ending in a circular or semi-circular shape in plan (resembling the head of a doll), mating into a similarly-shaped recess in the top of the receiver, designed to resist the tendency of the barrels to pull away from the standing breech when firing. Because an action's centerpoint of flexing when firing is at the base of the standing breech, not at the hingepin, a passive doll's head extension makes an effective extra fastener, even without additional mechanical locks operated by the opening lever.