The AR-15 series of rifles is one of the most versatile long gun platform ever invented. Developed in the late 1950s, the AR-15 is available in broad array of calibers, from .50 Beowulf to .22 ...

The pistol caliber AR is an interesting variant on the AR-15 platform that is gaining a wider audience. Although internally different from a typical AR-15, ... from .50 Beowulf to .22 Long Rifle.