I currently have an 11.5" upper on a lower with a Sig Brace.  I have a Form 1 submitted to SBR another lower.  My original intent was to have 1 SBR lower and 1 pistol lower, and move the upper back and forth and possibly obtain another short barreled upper that could be used on either.  The reason for not SBRing two lowers is that I live 6 miles from the KY/TN state line and crossing state lines with a pistol is easier than with an SBR.  However now that the ATF has declared that an AR with a short barreled upper and a Sig Brace is a pistol if you fire it like a pistol, and an SBR if you shoulder it, I have a question.

If I SBR the lower w/ the Sig Brace, can I take it across state lines without notifying the ATF if I never shoulder it and fire it as an SBR in the other state?  I know that an SBR lower is only considered an SBR when configured as such, but in this case, the configuration doesn't change, only the method in which I would use it.

Best advice is to stop the charade.  Form 1 the pistol lower and put a real stock on it.  Form 20 when you need to cross state lines.

I'd go with the original plan. Keep a pistol lower handy for travel if you don't already have a 5320.20 form approved.

You can file a .20 for up to a year. SBR them both and file a .20 for a year months in advance.

MAHA

Best advice is to never stop resisting.

If you're really resisting then why even bother getting a Form 1, why not just slap a stock on it and call it good!?!  Everyone likes to act all tough and anti government from behind their key board, or when giving others advice.

SBR it.

The pistol brace is, well, a Pistol Brace.  

We don't do ourselves any favors by treating the NFA as something to avoid.