Moved to SC from NY 6 months ago, and not having to deal with thordsen stocks, spur grips or featureless builds is awesome.

I'm building out my first AR pistol and had a few questions. Started with a stripped PSA lower, put a BCM lower parts kit in and have a 12.5 BCM upper on the way with an SBA3 brace to go with it.

Question is, if I were to make this into a registered SBR, I have heard you can't carry it across state lines. If it starts as a pistol, then you register it as an sbr and put a stock on it, can you just swap back to a brace if you want to travel with it? Or does it stay considered an sbr once converted? I'd like to eventually put a real stock on it but don't want to be limited to where I can go.

Build it as a pistol first, SBR it, put it back into pistol configuration if crossing state lines.

Thank you