HiBC, when one makes comparisons between ported and nonported barrels' muzzle velocity, they better both have the same bore and groove diameters. Same firing pin impact force on the primers, too. And the same lot of ammo's got to be used. There's easily a 50 fps spread in muzzle velocity with the same load across several rifles of the same make, model, caliber and barrel due to tolerances in their bore and groove diameters.
Last edited by Bart B.; October 25, 2012 at 06:51 PM.