Hello, for my case of shooting 240 gr Hi-Tek coated lead bullets, it was leaving powder burn marks and lead residue at the end of the cylinder between the cylinder flutes. Unsightly after about 150 rounds fired but wipes away easily with a lead-away cloth on my S&W 629-6. I haven't seen any etching of the cylinder yet but I've only had the 44 Mag a few months with about 700 rounds through it.