We know AR-15 rifles! We sell AR upgrades that make sense. From precision long range shooters to a close quarters short pistols we do it all. The AR platform is one of the most versatile rifle types ever made. The original AR-15 was chambered in 5.56 or .233 as a civilian caliber. Recently manufactures have introduced new calibers such as 6.5 Grendel, 224 Valkyrie, 458 SOCOM, 450 Bushmaster, 7.62X39 and 300 blackout. Because of this the traditional AR platform has become specifically specialized, allowing the end user to hone in on their shooting style. At GM Firearms we can help you choose the right setup and caliber for you.