Re: Building an SBR and NFA rules???
Just one lower. You may buy as many SBR uppers as you wish. I wouldn't have a complete NON-SBR lower sitting in your safe with a bunch of SBR-uppers.
You can SBR one lower. On the Form 1, you must put a barrel length. Let's say 11.5.... You get the stamp approved and in your possession. You may now put the 11.5 upper on your lower. You decide you want a 9" 300 Blackout upper. You go buy it, you may carry the SBR in that config. You decide you want a 14.5" upper, you may carry the SBR in that config. You decide you want to slap a 18" Mk12 upper on the receiver, you may carry the SBR in that config. As long as you can easily return the SBR to the 11.5" upper - you can have as many uppers for the ONE SBR lower as you like. One lower, one stamp. The stamp is only for the lower.