I shot 357 Mags through my 357 Max barrel twice and quit. When I cleaned the barrel after shooting the Mags there was always a lot of shaved pieces of the copper jacket in the barrels. It seemed like that some of the jacket was shaving when it hit the rifling. Do not know if it hurt anything, just did not look right to me so I quit. It has been about 12 years ago now and I did not have a scope on the barrel so I really do not know what the accuracy was like.