AR15s can also be chambered in several other ammunition types, such as .22 Nosler, .224 Valkyrie, .204 Ruger, .6.5 Grendel, .6.8 SPC, .300 Blackout, .350 Legend, and .450 Bushmaster. AR15s can shoot pistol ammunition, such as 9mm, .40 Smith & Wesson, and .45 ACP. The key to ...