IF YOU HAVE NOT BUILT YOUR .300 BLK OUT THEN YOUR ARE MISSING OUT IN YOUR WAR ROOM AFTER YOUR .223 IS COMPLETE YOU MUST AND I SAY MUST HAVE A .300 BLK OUT READY FOR YOUR SECONDARY LONG RIFLE/PISTOL
*****Ammunition Notification***** Grid Defense test fires every custom upper to verify cycling. We do not guarantee cycling with all ammunition due to vast differences in the quality of ammunition. We will only warranty cycling with US made ammunition. We will not warranty cycling with imported, steel cased or reloaded rounds.