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 Wilson Combat SPR Gallery Most Popular So What’s Next? Jim Cirillo’s 1-2-3-6 Drill Be More Than A Bodyguard Which Shotgun Safety Is Best? Grocery Stores Lining up for Ammo Vending Machines Review: Smith & Wesson Model 1854 Rifle