Only true AR-10 is the Armalite AR-10. Rest are imposters. From testing you are getting very little in velocity after you reach 16 inches. So I'm reevaulating wanting a 20inch barrel. I'm now looking at 16 AR-10 and putting a nice scope on it. This will greatly reduce weight and make it balance better. I've already got ammo and 10 armalite mags just waiting on the rifle.