Thread: Corroded brass

Once used brass.....seen this before?
Some kind of corrosion around every little knick and scratch.
Is it Ok?

How old is the brass?
I had a new case come up with similar but much fainter markings after it's first firing, I crushed and binned it.
The green colour suggests it is copper corrosion, I wouldn't be using it, the copper-zinc alloy case is the only thing between your face and the burning powder.

Hornady brass only fired once so virtually new. left these in the magazine for a few days to see if it would soften the spring and they come out like this.

Originally Posted by YosemiteSam

Hornady brass only fired once so virtually new. left these in the magazine for a few days to see if it would soften the spring and they come out like this.

Does the inside of your mag have discolouration?. Wondering if the source is in the brass, or something in the mag. If it were me I'd tumble the cases out of interest to see whether it was just superficial, but I'd take care to keep them segregated from others.

Originally Posted by YosemiteSam

Hornady brass only fired once so virtually new. left these in the magazine for a few days to see if it would soften the spring and they come out like this.

Maybe electrolysis between brass and magazine steel?

Could be bore solvent/oil etc on your mag.

Originally Posted by YosemiteSam

Hornady brass only fired once so virtually new. left these in the magazine for a few days to see if it would soften the spring and they come out like this.

Hi @YosemiteSam

Re the corrosion, dunno - what did you have on your fingers? It looks like some ancient ammo I accidentally spilled copper remover over. Try putting unfired brass in and leave a few days.

Leaving a spring in its compressed state is no different from leaving it in its released state - no problem either way. That's why you can leave your bolt action with the firing pin cocked and no problem - probably less of an issue than might be caused by repeatedly dry firing it every time you close the bolt and put it into your safe.

Working (alternately compressing and releasing) the spring a LOT helps, a bit. Compressing the spring to around/past its elastic limit will definitely weaken it. Or just put one or two less into it if you can do with one or two less magazine capacity. Maximum capacity of a magazine is not necessarily optimum capacity.

My 2 cents looks like what hoppes does to brass if left in contact.

I have had the same but worse comparing to your pics. Shot an ipsc stage at our club with the AR. It was surpressed at the time, ammo was brand new shiney hornady off the shelf stuff when it went into the mag. When i unloaded it 10mins later it was black with soot and corroded green like a battery terminal can get like. It looked like it had aged 70 years in a matter of minutes.

I measure my cleaning times with a calander so probably no solvents etc in the mix, mags were possibly the GI alloy ones if i recall rightly. Hope this helps.

Funnily enough i have never seen this happen again but ive never shot with a supressor again either.

It’s only 5 cases for safety sake throw it away

I'll bet it's completely superficial. Five seconds with Autosol and a rag will tell you. If they don't look mint after that, bin them.

Thanks guys. I'll consider them suspect but will also clean them just to see what happens. When I put these in the mag it had probably been a week and a half since I cleaned the rifle, but there could have been some cleaner still in the action. I use ballistol most of the time but now and again use some bore foam to remove copper, conceivably that was on the magazine follower though I'm usually pretty good at keeping the foam south of the chamber.

looks like cleaning shidders to me. I used to get it when I was a bit enthusiastic with the brushless bore cleaner and it would leak into the mag well.