“A half-century later, AR-15s and M-16s are made in varied forms by multiple manufacturers, and updated versions, including the M-4 carbine, remain the standard shoulder-fired weapon for most American service members and many allies.Civilian versions have many trade and model names, but are generally referred to as AR-15s, although this name is a rough description and does not indicate whether a particular specimen of the rifle is capable of both semiautomatic fire and automatic fire, or is semiautomatic only.”