At one time I had a rifle which would need cleaning after 10-12 rounds were fired. This gun would shoot bungholes and after 12 rounds it would open up. I always would clean the bore and fire a fouling shot. The next shot was always on. When I ran patches I never took 100% of the copper out of the barrel . I heard a barrel maker say to leave a small amount of copper. The barrel would shoot better and if you cleaned down to steel you were just wearing the barrel out quicker. And with the primers and powder you have today you should have no worry, But I have some 308 machine gun rounds that I always clean .nasty buggers.