I have sent a total of 27 rounds down range out of my Lyman GPR. That is how new I am to shooting black power rifles but, I have experience elsewhere.
I primarily collect and shoot military guns, and they are all cleaned with steal rods, have been for a long time. When looking at old military guns it is not uncommon to see measurable muzzle wear. This is attributed to the erosion caused by shooting and cleaning rod wear. As an avid service riffle shooter I take extreme caution not to prematurely wear the muzzle by cleaning with out a centering guide.
I do not load my ML without a centering guide.
Steal of any type will wear a muzzle faster than wood, brass, or fiberglass, basic rules of harder material does more damage faster. In fact for competition, shooters have some nifty plastic and Teflon coated steal cleaning rods and they still use centering guides to prevent barrel and muzzle wear.
My advice is to get a centering guide and use it on the range.
Ditto on all the aluminum oxide stuff, that was a well written post.
