AE - Action express
AP - Armer piercing
BAR - Browning Automatic Rifle
Bore - The inside of a gun's barrel
BP - Black powder
Burn Rate - The speed at which gun powder burns
Cal. - Caliber of a bullet
Choke - The end of a shotgun barrel
DA - Double action
DAO - Double action only
FMJ - Full metal jacket
FPS - Feet per second (measures bullet travel time)
FTF - Failure to fire
HD - Home defense
LOS - Line of sight
Mag. - Magazine
MV - Muzzle velocity
NFA - National Firearms act
SA - Single action
SMG - Sub machine gun