Yep - the difference between my 6" barrel handgun with .357 rounds and my 16" barbell carbine with same rounds is from 1280fps to 1640 fps - close to 30% more "get there quicker". I wonder what the gain on this is.
Muzzle velocities:
M4, 14.5” barrel: 880 meters per second, 2900fps
M16A1 20” barrel: 948 meters per second, 3110fps