The Ma., NJ., CT. compliant model of the S&W M&P10 has a barrel that carries it's diameter/weight all the way to the end of the barrel. It's not a bull barrel by any means. However it closely resembles what Colt calls their HBar barrel. According to the S&W specifications, it weighs exactly the same as their other model. Guess the amount of extra metal left in the barrel is exactly offset by the missing weight of that big ole S&W flash hider. Personally, I don't think I'll ever shoot my Big Ten fast enough or long enough to notice any differences. Iffin' I shoot a 308 fast enough to change POI by heating the barrel, then I definitely am gonna change POI more with the soreness of my shoulder. Besides, I ain't man enough to hold the muzzle down while doing tricks like that. Recoils gonna' make more difference that any barrel heating I'm gonna' do.