Glossary of firearms terms

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Pan
Of a matchlock, wheel lock or flintlock gun, the receptacle for holding the priming charge.

Paster
A sticker of the appropriate size and colour to cover a bullet hole in a target.

Patch
1 Of a muzzle loader, a wrapping of leather, cloth or paper, usually greased, placed over the muzzle of a rifle when a bullet is rammed into the rifle to provide a closer fit between the bullet and the bore.
2 On high velocity ammunition, a hard metal jacket encasing the lead core of a bullet to minimise lead fouling, to improve the bullets ability to take the rifling, to flatten the trajectory and to maximise accuracy.

Patron
1 Paper cartridge first used for pistols and later for muskets.
2 An early type of cartridge box made of wood, leather, tin or iron, and dating from the 17th century.

Penetration
Of a projectile, the distance travelled into the ground, armour or other substance before exploding or coming to rest. Pine boards seven eights of an inch thick, placed at given distances are generally used for testing purposes.

Pepperbox
A handgun characterised by three or more barrels grouped around a central axis. Popular in the mid 19th century, pepperboxes vary greatly in size and number of barrels. Most used the percussion system.

Percussion arm
Any weapon designed to fire by means of a percussion cap.

Percussion bullet
A bullet equipped with a percussion cap which, on impact explodes to detonate a powder charge also contained within the bullet.

Percussion cap see Primer

Percussion lock
1 An ignition system based on the principle of percussion, meaning caused by a blow.
2 Specifically an ignition system in which a priming charge is fired by a hammer blow on a percussion cap. The percussion lock superseded the flintlock in the early 19th century.

Petronel, Petrinal, Poitrinal
A post medieval (variously dated in the 14th, 15th and 16th centuries) hand arm, generally hung about the neck on a lanyard and fired with the appropriately shaped butt end flush against the chest. Intermediate in size between an arquebus and a pistol, the weapon was short, heavy and of large calibre. It was carried chiefly by horsemen.

Petticoat
The narrow painted circle bounding the white on a target and marking the limit of the scoring area.

Piece
A term applied to any firearm under discussion.

Pill lock see detonator

Pilot model
An experimental model of a new weapon.

Pistol
1 Loosely, any weapon designed to be fired by one hand. In this sense revolvers are included.
2 A firearm designed to be fired by one hand, the bore of which is integral with or permanently aligned with the chamber. Both single shot and magazine pistols are in use. In this more precise sense revolvers are not included.

Pistol-carbine
A hand arm to which may be attached a stock to allow firing from the shoulder. Sometimes the weaponís holster doubled as a stock.

Pistol grip
The shape given to the small of the stock of a shoulder arm to afford a better grasping surface for the hand. A full pistol grip curves sharply downward from the stock, bending close behind the trigger guard. A half pistol grip or semi-pistol grip slants only slightly downward as a protuberance from the small of the stock.

Pitch
1 Of a screw, the penetration achieved by a single turn.
2 Of a gear, the interval between teeth.
3 Of bore rifling, the angle at which the rifling spiral has been cut relative to the bore axis. Generally pitch is computed as the inches of bore required for a complete spiral to be effected, for example "one turn in 15 inches". This measurement is often referred to as the twist of the rifling. The twist may be uniform throughout the bore or may increase as it nears the muzzle. The latter method, known as gain twist, provides maximum rotary motion to the projectile when it reaches the muzzle, while preventing its jumping the rifling at the shock of discharge. Such a spiral may begin near the breech at one turn in 20 inches, increasing to as much as one turn in 10 inches at the muzzle.
4 Of rifle and shotgun stocks, the angle at which the buttplate slopes relative to the bore axis.5 Of pistol and revolver grips, the angle at which the grip inclines relative to the bore axis.

Plane of sighting
In ballistics, the vertical plane containing the line of sighting.

Poitrinal see Petronel

Portable firearm
Any firearm capable of being carried by soldiers in the field.

Post sight see Sight

Powder
Any propellant explosive. Black powder is a mechanical mixture of fully burnt charcoal, sulphur and saltpetre. It burns with considerable white smoke. Brown powder is similar to black but is made from under burnt charcoal. Smokeless powder is a chemical mixture usually built around nitrated cellulose and surface coated mechanically to burn with a minimum of smoke and ash.

Pressure
The thrust of expanding gasses at the time of discharge, normally stated in pounds per square inch. Chamber pressure designates the expanding gas pressure of the exploding charge as generated against the chamber walls and breechblock. This measurement is often incorrectly termed breech pressure. Residual pressure designates pressure remaining within the chamber after the bullet has left the muzzle. The measurement applied usually to automatic weapons.

Prime
To prepare a weapon for firing by placing a primer or priming powder in a position suitable for igniting the propellant charge.

Primer
The device that detonates when struck, igniting the propellant charge of a cartridge. In centre fire fixed ammunition the primer occurs as a cap like attachment to the cartridge base. Originally the primer contained chlorate or a fulminate, though compounds having guanyl as a base are currently employed. Initially the primer was separate to the cartridge and called a percussion cap, it consisted of a metal cup holding the explosive and weatherproofed on its open end. This cup was placed on a percussion weapons cone or nipple with the open end down. The hammerís blow detonated the primer and this in turn ignited the propellant charge through the ignition vent.

Primer, Maynard
The Maynard primer was a variant of the percussion cap and resembled the caps in a childís cap pistol. Pellets containing explosive were sealed at appropriate intervals between two strips of paper. The resulting tape, having been rolled, was inserted into firearms designed to receive it and cocking the hammer brought a pellet into position over the ignition vent leading into the chamber.

Priming pan see Pan

Projectile
1 The bullet of a small arm. The elongated projectile used in most modern firearms was invented in 1662 by the either Bishop of Muenster or one of his followers.
2 In ballistics a bullet does not become a projectile until it is in flight.

Propellant, Propellant charge, Propelling charge
The explosive which when placed in the bore behind the projectile and ignited, expels the projectile from the weapon. In a cartridge the propellant is the powder charge.

Pump action see Action, slide

Pump gun
1 A repeating rifle reloaded by means of a lever, suggesting a pump handle.
2 A weapon with a slide action.

Pyramidal sight see Sight

Pyrites
Metallic sulphide, a mineral possessing the property of producing sparks when brought sharply into contact with steel or iron. Pyrite was used to produce sparks in wheel lock and early flintlock weapons. Flint had more suitable qualities for ignition and eventually superseded it.