So, I’ve noticed that I get some blue residue on my muzzle devices a couple days after shooting. Is this copper fouling? Should I worry about it at all?
Most likely copper residue reacting with residual bore solvent.
Some Hoppes #9 or BF Foam Bore Cleaner on a Q-tip should have it off in no time.
ETA: If you follow the link below it will take you to my BF FBC cleaning tutorial. There you’ll see how using BF FBC to clean the bore, fills the entire barrel from locking lugs to flash hider.
Excellent.
Any problems with just leaving it on there?
I can’t think of any, no. It will most likely just continue to accumulate.
But why leave it? When it’s so simple to remove. 