12.5 inch barrel vs 13.7 inch barrel velocity

[SHARPSHOOTER282]

I’ve built a 12.5 mid length gas system and a 13.95 mid length. I can get you some fps with Winchester white box, pmc, or federal 223 and 5.56. It might be a while, but happy to run some numbers next time at the range with chrono.

Cheers , that would be cool