by Shooting Illustrated Staff posted on April 11, 2011 Guns Support NRA Shooting Illustrated DONATE Resurrecting the 6x45 mm cartridge, Spirit Gun Manufacturing's SGM-A41 is a high-performance, yet practical, take on the AR platform. In this article 6x45, AR, semi-auto rifles, Spirit Gun Manufacturing Related Stories Spirit Gun Manufacturing SGM-A41 Barrett REC7 in 5.56 NATO Gallery Colt Match Target M4 Case-Head Swipe Barrett REC7 in 5.56 NATO Most Popular Home Defense Pistol Skills New Pistols for 2024 Total Control New Lever & Pump Action Rifles for 2024 Shotguns and Magazines Drills for the B-8 Target