The “AR” in “AR-15” rifle stands for ArmaLite rifle, after the company that developed it in the 1950s. ... AR-15-style rifles can look like military rifles, such as the M-16, but by law they function like other semiautomatic civilian sporting firearms.
While often referred to as an “assault-style” weapon, the AR-15 is, by definition, not actually an “assault rifle,” but rather can be categorized as a semi-automatic weapon. An assault rifle means the weapon is fully automatic, and the AR-15 does require a trigger pull for a bullet to leave the barrel.
Many hunters prefer using AR-15 style rifles because of their versatility, accuracy, wide variety of available features, and wide variety of calibers (see below). Collapsible stocks are convenient for hunters who pack their rifles into remote hunting locations or for length of pull adjustments to fit any sized hunter.