Copper Oxidation

[Aught Six]

I was examining my AR-15 the other day and found a bit of oxidized copper fouling at the mouth of the muzzle and inside the flash hider. The barrel was a little fouled, but I had to run Hoppes through a few times before I started seeing hints of blue on my patches (I don't like running the heavy copper solvents through chromed barrels).

I'm not a clean freak, but it still surprised me to see that blue fouling. Any idea what was cause it to be so pronounced? I've fired Lake City SS109 and Federal American Eagle through it, maybe 400 rounds since the last field stripping. No super cheap or foreign loads.

[Red Lion]

You can shoot the most expensive amo and still get copper build-up. It is just par for the course, as every rifle will experience it. I also do not think that you are going to do any damage to the barrel by using copper solvent, but clean as you wish.

[Roskoe]

You don't often see the blue copper deposits around the muzzle of regular rifle barrels that don't havea flash suppressor. There must be a certain amount of atomized copper following the bullet down the barrel, the way the copper builds in those AR-15 flash suppressors.

And that oxidation can cause pits. I used to only decopper my gun every year or more. But years ago, I learned the hard way

[thndrchiken]

I use Hoppes #9 for powder fouling and to brush the bore. After is looks clean I then run a couple patches of Shooter's Choice copper solvent it any blue comes out it gets brushed with the SC and a nylon brush. As long as you don't let it sit in the bore too long you'll be ok.

[Aught Six]

Thanks for the info, guys.