Has anyone besides me chronographed any factory ammo in a 20" Ar-15 ? I've shot several brands and styles and never got the advertised velocities. I know a 20" barrel won't do what a 24" will, but Military specs call for M193 (55 grain) ball to run about 3200+ and the all stuff I have tried that was advertised as "military spec usually ran just over 3000 FPS in my 20" Ar.
Maybe I have a faulty chrono ?
Maybe I have a faulty chrono ?