The best AR-15 pistols are for sale here. The AR-15 is the world's most popular gun platform. Also known as the AR15, or AR 15, the AR-15 design allows for many different styles of shooting and gun types, including the handgun or pistol format. Chambered primarily in 5.56mm NATO/.223 Remington, the AR-15 pistol is a hot new design and we stock quite a few of them. You can find AR-15 Rifles here, AR-15 Parts, AR-15 Magazines, AR-15 Pistol Grips, and AR-15 Lower Receivers.