gunner_lee
Well-Known Member
I got my stamp in (mailed 12/4, received 12/7, pending 1/4, approved 4/16) for my .300 BO SBR. The lower is the one with the serial number and engraving. Can I put a different caliber short barreled upper on that lower as long as it isn't a "permanent change"? ex- want to put a 7.5" 5.56 upper on the same lower.) TIA. BTW, I love the blackout SBR- running a 8" AAC barrel/gas block with my YHM Phantom suppressor. Scwiiiiiiiing!