Let's talk SBR legality here for a minute

GA Firing Line

chance

Tracker
Jul 15, 2015
958
1,073
113
Ga
Zip code
30101
There's no such thing as a "permanent change" to an AR lower when it comes to barrel length or caliber.
Exactly. Thats why I wouldnt notify them for an AR.
Do you literally just mail them a letter? Not like an official form...
Yea just mail the NFA branch a letter with the pertinent info (trust name, Serial, etc) and let them know that caliber or OAL changed.