AR-15 Breech Rust

[Metal Magic]

Hey everybody, anyone ever get rust developing in the barrel breech? I just recived a new upper and after 300 rounds and two cleanings I would imagine I have developed some copper fouling? I would say it is a dark brown/red coating on some parts of the breech. I am sure it is not rust just kinda curious what it is? Carbon build-up? Copper fouling? Wear ? Is it worth scrubbing or is it unavoidable? I use CLP pretty liberal on the BCG and give the whole rifle a light coat inside when storing in the safe. Never noticed this kind of build up on my pistols, shotguns, or .22 rifles.

[0351USMC]

are you shooting russian ammo?

[Metal Magic]

No sir, just Federal .556

I am about 99.9% sure no corrosive ammo has ever gone down the tube.

[Metal Magic]

my mistake, discoloration is on the teeth of the barrel extension not the actual breech

Here is a pic of what mine looks similar to

[G38xOC]

^ that looks normal wear to me

i could be wrong

[0351USMC]

Yeap,normal wear..

[wash]

Pretty normal. I think most extensions are made of tool steel to deal with the shock loads, not stainless at all.

I think that's just a combination of very minor surface oxidation and powder residue with perhaps a hint of bullet jacket shavings.

At the rate it's progressing on my guns, I'm sure the barrel will be shot out or I'll be a very old man before it needs fixing.

[Metal Magic]

Thanks for the input guys. I am sure it is nothing to sweat, I might take some time tomorrow to do a little scrubbing with a brush and see if any breaks away.

I guess it would be impossible to keep the unfinished barrel extension clean without packing it with grease.

[donking]

Just wait, once you get the wearing on the brass deflector you won't even notice the barrel extension anymore.

And then theres the wear on the upper receiver from the cam bolt, oh lord these ARs just start falling apart once you shoot them a few thousand times.

[Mail Clerk]

Hey everybody, anyone ever get rust developing in the barrel breech? I just recived a new upper and after 300 rounds and two cleanings I would imagine I have developed some copper fouling? I would say it is a dark brown/red coating on some parts of the breech. I am sure it is not rust just kinda curious what it is? Carbon build-up? Copper fouling? Wear ? Is it worth scrubbing or is it unavoidable? I use CLP pretty liberal on the BCG and give the whole rifle a light coat inside when storing in the safe. Never noticed this kind of build up on my pistols, shotguns, or .22 rifles.

Metal Magic,

Your sure it on the barrel breech OR your bolt face???? Is that what you mean??? If it's the ladder then I think it's primer sealant. Since you coat your barrel with oil it's hard to believe it's corrosion.

Mail Clerk

[1911su16b870]

Have you tried a AR chamber brush?