Form 1 SBR questions

[Troutguide]

The way I understand it is if you first build a pistol it can be converted to a rifle later as long as you don't make an SBR(change the short barrel out first) at any point then you are fine and can actually convert it back to a pistol later. How to confirm this process is hard to say.

This might help:
https://www.atf.gov/file/55526/download

https://johnpierceesq.com/which-buffer-t...ar-pistol/