I'm working on my 308 SBR project currently waiting on a stamp form the ATF. It then dawned on me that if I'am running a 12.5 upper on it, I will have to notify the ATF that I want to move it across state lines. Now my question for anyone who can answer this is, If I put on a upper that is longer than 16 inch ie 18, 22 etc. Do i still have to notify the ATF that I'm taking the my SBR'd Lower out of state?
To my best knowledge, the SBR lower is not considered a NFA up if it barrel length and overall length are out of the limits set by the BAFT NFA.