If you use a rifled slug barrel with shot shells eventually you will wear down the rifling.
Interesting, how does soft clean lead wear down rifleing in a hard steel bbl.?
"If" that was the case, there wouldbe holes all overevery used muzzle loader bbl. all over the country side!!!! Also all of my revolver bbls would have been worn very thin by now, as some have nothing but thousands upon thousands of lead bullets shot through them!!!
Drilling Man