M-pro 7 is good stuff, but youy need to also use the "Gun Cleaner" alternately with the "Copper remover' for the best results. This is because the carbon & copper are layered like plywood. The "Gun Cleaner" also neutralizes the "Copper Remover".
Also don't be upset when you see no blue or green. Thats a product of ammonia-based metal solvents. M-Pro& is not ammonia based & the removed material is black or tan in color.
Allan Quartermain: “Automatic rifles. Who in God's name has automatic rifles”?
Elderly Hunter: “That's dashed unsporting. Probably Belgium.”