I've run over 300,000 reloads (FMJ, cast, coated, moly, plated, frangibles) thru my Glocks in competition shooting using both OEM barrels and hand fitted BarStos and LoneWolfs. That's not really the issue. Problem is using someone else's reloads and not your own. Cook your own loads so you know the quality of the ammo. Also because of leading using cast bullets. Leading builds faster in a 9mm than a .45acp because of the velocity, and the % reduction in diameter occurs much quicker. It's also a huge PITA to clean lead from an OEM barrel, versus a SS rifled barrel.