Submitted my Form 1 to SBR my pistol lower. It's an 11.5" upper so I put down 31.5" on the overall length. I had a buddy just do a measurement on his 11.5" upper with a SOPMOD stock on a 6-position buffer tube and got 29.5" without the rubber butt pad. Would there be any issues with the ATF on this by over estimating my overall length? Say my Form 1 is approved, is it recommended that I notify them my overall length is shorter than declared? I plan on using a 6-position BCM tube along with the B5 BRAVO stock.

Thanks!