IANAL, but it seems to me after reviewing various statements and opinions from the AG that building an AR in a caliber other than .223/5.56 would also be legal. Say .458, .300 BLK, 6x45mm, 6.5G, 6.8 SPC, etc.
I have the Kahr P380. It is IMO the best pocket pistol ever made. Mine has been completely reliable through hundreds of rounds (mostly S&B). It shoots more like a tricked out race gun than a pocket gun, recoil is slight and it tracks straight up. Accuracy is phenomenal for such a small gun.
It would seem to me that they'd be legal, as would AR-15s in any caliber other than .223/5.56. But then, I'm definitely no expert on the convoluted laws here. It was much easier at my previous bases :blah:
Got stationed here end of last year, made sure I made it before 10/1. Thought I'd already posted an intro, but apparently not. Anyway, been in the AF for just about 15 years. Currently stationed at Ft. Meade and living in Severna Park.