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 Review: Staccato C Pistol What's the Best 38 Special Ammo for Self-Defense? First Look: Wilson Combat Division 77 Project 1 First Look: Ruger RXM Pistol Best Distance to Zero a Pistol-Mounted Red Dot Marines Reach Early Full Operational Capacity with New Sniper Rifle