The stamp finally came back for my NiteScout A3 SBR. Here’s a picture of it with a Magpul ACS stock (necessary to get it to MD-compliant 29″ OAL):
Suffice it to say, it’s infinitely more usable with that stock attached. Still on the heavy side for a pistol-caliber carbine, but it balances well. With an optic, I think it’d be a pretty rocking PCC SBR.