It used to be that an AR-style carbine chambered in a pistol caliber like 9mm Luger was a special gun used only by law enforcement or the military. Then some people discovered it was much less expensive to shoot than an AR chambered in .223 Remington. And while that hasn’t changed, more and more people have found that an AR chambered in 9mm Luger is great for fun, competition and even self-defense.

CMMG was founded in 2002 and has designed its own AR-style pistol caliber...