yes i did clean the barrel often, after every box (5 rounds), i inspected the barrel. it was spotless everytime with the exeption of the brennekes, they foul the barrel with leadBAD.dont get me wrong tho, they are great slugs.. i did also forget to add, i had an OLD box of the 3" federal "HI SHOK" foster slugs, they were acceptable. grouping slightly less than the brennekes and copper solids