Firearms Glossary
Comprehensive dictionary of firearms terminology with 18 terms.
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+
+P Plus P
Ammunition loaded to higher pressure than standard, producing higher velocity. Verify firearm is rated for +P.
+P+ Plus P Plus
Ammunition loaded to even higher pressure than +P. Use only in firearms specifically rated.
B
BC Ballistic Coefficient
A measure of a bullet's ability to overcome air resistance. Higher BC = better long-range performance.
Bullet Drop
The vertical distance a bullet falls below the line of bore due to gravity.
C
Centerfire
Ammunition with the primer located in the center of the cartridge base.
E
Elevation
Vertical adjustment on sights to compensate for bullet drop at various distances.
F
FMJ Full Metal Jacket
A bullet with a soft core encased in a shell of harder metal, preventing expansion on impact.
FPS Feet Per Second
Unit of measurement for bullet velocity.
G
Grain gr
Unit of weight measurement for bullets and powder. 7,000 grains = 1 pound.
J
JHP Jacketed Hollow Point
A bullet with a hollow cavity designed to expand upon impact, increasing stopping power.
M
Muzzle Energy
The kinetic energy of a bullet as it leaves the barrel, measured in foot-pounds (ft-lbs).
Muzzle Velocity
The speed of a bullet as it leaves the barrel, measured in feet per second (fps).
P
Primer
The component in a cartridge that ignites when struck by the firing pin, igniting the powder charge.
R
Rimfire
Ammunition where the primer is located in the rim of the cartridge base (e.g., .22 LR).
S
Subsonic
Ammunition with velocity below the speed of sound (~1,125 fps), often used with suppressors.
Supersonic
Ammunition with velocity above the speed of sound, creating a sonic crack.
T
Trajectory
The curved path a bullet travels from the muzzle to the target due to gravity.
W
Windage
Horizontal adjustment on sights to compensate for wind drift or zero the firearm.