Originally Posted by
ClassIIIGunsmith
I never thought that a .223 barrel could do the same thing as a 300win Mag. I have fired at least 300,000 round through my colt SP1, have never had a problem and this guy you quote molon says a barrel has a replacement mile stone. I know that 300win mag will start key holing if you shoot the gun agressively and shoot the rifling out of the gun. But a 223 really, why would you compare the two? The only time I've seen a derifled 223 barrel it was some 22 year old punk who sent 500 rounds out his dad's m16 giving it no cool down time. Back to the OP you should break in the barrel to deburr it. But clean the new barrel first it helps deburr it and removes the nasty powder residue from the factory pressure test. Bump fire a 30 round mag though the gun so it has no time to cool between each shot because the way to deburr the barrel is to melt/ burn the metal burrs off. Thats how I do it its faster and cheaper than using bullet friction alone. Or you can just break it in as you use it and you'll get tighter groups as you use it.