has any one had any copper build up in the barrel of your hand guns? If so how would you recommend removing it.
can you describe your normal cleaning method[s]?
More frequent cleaning (if applicable) but I also recomend using Hoppe' s#9 nitro solvent
My break in period with my 9mm AR yielded lots of copper and Brass shavings/buildup. I used a wire brush followed by foaming bore cleaner. I used gun scrubber for the reciever. But remember that scrubber is nasty shit- do it outside, let that shit evaperate, the wipe it down. The assembly with look brand new. After that thin lube everything and wipe down-like new.