The Definition of Sectional Density
The relationship between a bullet's weight and its diameter. A long bullet, such as the original 7.62x54R
loading for the Mosin Nagant 91/30, will have a high sectional density and consequently greater
penetration than a shorter bullet of similar construction. A shorter bullet with less sectional
density will have relatively less penetration, but greater knockdown power.
19 Other Firearms Definitions You Need To Know
A rifle with a relatively short barrel.
A semi-automatic is said to be out of battery when the slide fails to come all the way forward again after the
gun has fired. This condition can be created by a misfeed, a dirty gun, weak springs, the shooter's
thumbs brushing against the slide, riding the slide, or any of several other causes.
The process of assembling cartridge case, bullet or shot, wads and primer to produce a complete cartridge with the use of
hand tools in the interest of loading for firearms for which cartridges are not available, experimenting with loads
to achieve better performance, or to save money. Not to be attempted without knowledgeable instruction and careful study of the process.
Targets that do something when you hit them, such as fall over, burst, send up smoke, or make a noise.
A musket shortened for cavalry use.
A small hole in the barrel of a gas-operated firearm through which expanding gases escape to power the autoloading system.
A firing pin which moves freely forward and backward in the breechblock.
Expanding the neck of an existing cartridge to make it use a bullet of a different caliber. A typical process used in the creation of wildcat cartridges.
Abbreviation for Accidental Discharge
Refers to a visible dark ring created by the primers in centerfire ammunition around the firing pin hole in the frame after much use.
A double-action semi-automatic firearm which is designed to have a much lighter trigger pull than is usual for a double action.
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.
A metal surface which contains a pattern of ridges or beads.
The first shot from a rifle that has been cleaned, and not fired recently may go to a different point of impact, for the same point of aim than a rifle that has been fired recently.
This first shot is referred to as a shot from a cold, clean, bore.
To jerk a firearm off target inadvertently in the instant of firing in timid anticipation of recoil. Commonly caused by learning to shoot with a gun more powerful then they are ready for.
Abbreviation for 'Back Up Gun'
Recoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action.