by Shooting Illustrated Staff posted on October 13, 2011 Guns Support NRA Shooting Illustrated DONATE Primary Weapons Systems goes out of the box in AR design. In this article 5.56 NATO, 7.62 NATO, AR, Primary Weapons Systems Related Stories Primary Weapons Systems PWS MK116 and PWS MK216 Carbon-Fiber Rifle Round-Up AR-15 Muzzle Brakes Gemtech Suppressed Bolt Carrier 14 New Rifle-Caliber Pistols for 2019 Most Popular New Guns for 2024 The Beginner's Guide To Defensive Knives Essential Concealed Carry Accessories Tech Wisdom: Plastic Training Ammunition? Best Barrel Length for a Shotgun? Reloading On The Fly