Letter P

The Definition of Parallax

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Parallax

This occurs in telescopic sights when the primary image of the objective lens does not coincide with the reticle.Telescopic sights often have parallax adjustments to minimize this effect.


19 Other Firearms Definitions You Need To Know


Sporterizing

The practice of modifying military-type firearms either to make them suitable for civilian sporting use. Common sporterizing includes changing the stock or sights.

Stopping Power

A popular but imprecise term used to refer to the ability of a small arms cartridge to cause a human assailant or an animal to be immediately incapacitated when shot with it. A more precise term is be Wound Trauma Incapacitation (WTI).

Sight Alignment

The manner in which the sights are lined up properly in front of the shooter's eye, to form a straight path to the target.

Biathlon

A shooting sport that combines both skiing and rifle shooting. It is the only shooting activity in the Winter Olympics. There is also a summer biathlon which involves running and shooting but it is not yet an Olympic event.

Pull

The entire process of making the trigger complete its journey past the trigger break.

Inletting

The process of carving out recesses in wooden stocks with precision, using gouges, chisels and scrapers to accept the steel components of a firearm.

Cartridge Trap

A compartment built into the buttstock of a long gun, usually with a hinged cover, in which are drilled holes deep enough to hold several spare cartridges of the type suitable for use in the specific gun.

Explosive

Any substance (TNT, etc.) that, through chemical reaction, detonates or violently changes to gas with accompanying heat and pressure.

Chamber Throat

This is the area in the barrel that is directly forward of the chamber, which tapers to the bore diameter.

Follower

A smooth, sometimes contoured plate, within a magazine, at the top of a spring, across which cartridges slide when being loaded into a chamber.

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.

Loaded

A firearm is loaded when a cartridge is in its firing chamber. However, for safety reasons all firearms are always treated as loaded at all times.

COF

Abbreviation for Course of Fire.

Mouse Gun

A name for any palm sized handgun which fires a small caliber.

Headspace

The distance, or clearance, between the base of a chambered cartridge and the breech face (or bolt face) of a firearm. This is a critical dimension, particularly in high powered rifles. If there is too little headspace, the bolt will not close. If there is too much headspace the cartridge will not be properly supported in the chamber and the cartridge will expand upon firing and may rupture, blasting high-pressure gas into the action and possibly into the body of the shooter. Headspace should be .003" - .006" in a centerfire rifle. It can be checked with a set of "Go and No-Go" gauges specific to the calibre in question. (See below.) With a standard cartridge, the headspace is registered by the shoulder, with a belted cartridge, the headspace is registered by the forward edge of the belt.

Plus P

Also spelled "+P" or "P+". Is small arms ammunition that has been loaded to a higher internal pressure than standard for it's caliber. Many calibers are available in both standard and +p or +p+ variants. Ammunition marked +p produces more power and higher pressures than the standard ammunition. Not all firearms are designed to handle the increased pressure consult your owner's manual or gun manufacturer before using +P ammunition.

Drum Magazine

A type of firearms magazine that is cylindrical in shape, similar to a drum. Probably the most recognizable drum magazine is the magazine for a Thompson carbine rifle, also known as the Tommy Gun.

Co-Witness Sighting

Co-Witness Sighting is the use of any iron sight mounted onto a rifle that is fitted with an optical sight as a primary sighting system. They come in two basic configurations, fixed or flip-up. The idea is that if you align your red dot and your iron sights you have a backup aiming system on the gun.