sbr's

[skeety]

I own an M16A1 with a 20" barrel. Do I need another form 4 to put a 14.5" barrel on it?

[BWE Firearms]

No, Machinegun registration trumps SBR. You can put any barrel length on it you want. If you change the barrel length that the M16 will spend most of its time with NFA branch likes to be notified with a simple letter.