Thanks for the replies guys, but what I was asking is the diff in muzzle velocity between the two barrel lengths. Example, a bullet out of the 16" will be 150 fps slower than the 18".
I was looking for more precise info than what I was seeing on the net, like other peoples estimations and velocity numbers recorded at 50 & 100 yds from 14, 16 and 24" barrels. I just wanted to know what actual numbers they were seeing out of the diff length platforms. If I am left with no alternative but to guess, I'd say 40 fps per in. or 100 fps diff between the 16 & 18.6" bbls.
Mero