"My standard break-in for factory barrels these days is to shoot the thing, then see if it's fouling bad. If it is, then I "clean" the bore using 220-grit lapping paste on a patch wrapped around a bore brush. Unless the barrel's hopeless, this really smooths them up, without eroding the throat like fire-lapping. Most factory barrels respond well to being cleaned with JB the first few times. Custom barrels can just be shot, then cleaned every 10-30 rounds as fouling indicates. Doesn't hurt them a bit."
^^^^That's the answer!! ^^^^
I have not seen two manufacturers agree on break in procedure. Makes me think that their barrels are made from totally different metals.
I have to add however that I have had two barrels (one bought in Glasgow MT {300WM} and the other in Rapid City {280}, both cheap 700's made when Remington used molded rubber bands for stocks) that had tooling marks that looked like someone drug a heavy tool back out of the barrel. Fire lapping helped those a lot!. I've restocked those in wood and they are now two of my favorite rifles.
