Muzzle brake green buildup

[jetinteriorguy]

It’s been a while since I’ve shot my PSA AR10 in 6.5CM and just noticed a buildup of green verdigris where the muzzle brake meets the muzzle. It is also on the muzzle a little bit and extends into the brake up to just past the first openings. Is this a common thing or a problem with the brake? I’m assuming that some of the bullets jacket is being stripped off and deposited on the muzzle and brake leading me to think the brake is bad. Accuracy on the rifle Isn’t bad, it consistently shoots 7/8-1 MOA. I’ve never had this happen on any other rifles, and I have several with brakes in different calibers that I shoot more often than this one.

 

[Fishbed77]

Sounds like copper fouling. Clean it off with a solvent that will dissolve copper (not CLP).

 

[jetinteriorguy]

I’m not so concerned with cleaning it off as to why it’s doing this and fixing it. I’ve already cleaned it quite easily, but want to prevent it from happening again.

 

[rickyrick]

As long as the the bullet isn’t striking the muzzle brake, it’s probably a normal byproduct of shooting.
Basically all you can do is make sure the bullet passage is larger than the caliber of the bullet and that it is centered on the bore enough to allow the bullet to pass.
I have rifles with no brake that get a little green on the face of the muzzle at times.

 

[Shadow9mm]

nothing to fix. Your shooting copper bullets. some of that copper is getting deposited in your brake after firing, similarly to what happens in your barrel. The green is from the copper oxidizing. Clean it as needed.

 

[MarkCO]

nothing to fix. Your shooting copper bullets. some of that copper is getting deposited in your brake after firing, similarly to what happens in your barrel. The green is from the copper oxidizing. Clean it as needed.

Yep.

 

[jetinteriorguy]

Thanks, basically that’s what I figured since accuracy wise things seem fine. It cleans off pretty easy so just a maintenance issue then. I’ve just never encountered this before.

 

[Shadow9mm]

My brakes get buildup sometimes. turn green. comes off when I clean.

 

[jetinteriorguy]

The interesting thing is I have zero copper build up in the barrel. I guess it’s saving it all up for the muzzle brake. LOL.

 

[Shadow9mm]

could be the barrel is smooth enough the copper is not being deposited but it getting pulled off by the friction and is being deposited in the brake with the carbon my the gasses.

 

[hounddawg]

does it look like this? Only happens when I use 8208 XBR in my Grendel. Picture does not show the color just right, in reality it is sort of a pale greenish blue. I am guessing it is some additive in the powder, it cleans off easily

 

[jetinteriorguy]

does it look like this? Only happens when I use 8208 XBR in my Grendel. Picture does not show the color just right, in reality it is sort of a pale greenish blue. I am guessing it is some additive in the powder, it cleans off easily

Yup, I think your on to something since it cleaned off so much easier than I'd expect copper deposits to do. Although I don't have any deposits like this on my BCG, just the muzzle. I've only used H4350 as far as I remember, but I'd have to check my records since I may have tried Staball but don't recall off the top of my head. I got a really good deal on some blasting bullets a while back that still shoot 1MOA and may have used the Staball in them, or it could be for some reason these bullets have something about their jackets that's leaving these deposits.

 

[hounddawg]

it gets all down in my trigger group, bolt, on the firing pin etc. Cleans pretty easy though. I suppose if I tried to go 150 rounds between cleaning it could cause problems

 

[Rob228]

I've got a 10" 5.56 Armalite with a funky looking brake that gets this same thing. Cleans off pretty easy though.