The Russian Mosin Nagant Forum

Hi,

went through some old ammo I have had in storage for about 15 years, was in a cardboard box in a Bren Gun Magazine storage box. Other types of ammo was also in the Bren box also 7.62x39 copper looking case 7.62 NATO etc.

On the Russian 7.62 x 54 a blue growth has formed on some of the cases, looks like copper sulphate? When I scraped it odd an brushed with a brass brush some cleaned up ok others display small marks that when I probed were a actual whole in the case.

That's corrosion, dirty brass, contact with moisture, corrosive liquids, even long term contact with paper or cardboard will do this. If you have any brass or copper pipes in your home's plumbing have a look at them, likely you will find similar corrosion someplace on them. Pull the bullets for later reloading and toss the case. Best way to store ammo is loose in a USGI .50 ammo can, or any size GI ammo can. They have lids that seal air tight, toss in some desiccant packs, and the ammo will stay good for eternity. It's OK to leave the ammo on the clip, but cardboard box's contain chemicals in the papers makeup that will react with brass over time. Mostly a stain, yours looks more like a corrosive chemical got on it, bore cleaner maybe? I had a 55 gallon drum of clean brass pipe that the cat had been using as a pissing head, when we dumped it out the brass was all green and nasty like this.

I agree is some form of corrosion, my original thoughts was it may have something to do with the corrosive primers and the corrosion is from the inside out.
Thinking about your comments the ammunition could have been contaminated with bore solvent as some solvent get a blue/ green colour with the reaction to copper fouling. If the spray of a brush leaving the barrel or an old patch touches the case given 15 / 20 years it may cause this damage. Contamination with bore solvent I did consider, but I thought it would just be a growth, not an acid.

Bore solvent ( remove copper [ acid ]) + brass ( contains copper ) = corrission .

I will cut a case in half just for curiosity sake.

Just goes to show there is always something to learn.

Contact with leather will do it also, there is a reason why police officers favored nickel plated cases for the .38 special ammunition they carried in the old loop style belts. Tannic acid in leather will corrode brass, very badly corrode it given time, and not all that much time. I had green .357 magnum cases after less than a month in the leather loops of the belt I use for my Ruger Blackhawk. After that I switched to nickel plated cases, no more problems. The salts inside a primer are contained within the primers explosive compound, this would be for ammunition containing corrosive primers, mostly military . It's not an issue until the round is fired, the smokeless powder itself is not corrosive. Go back far enough and you have brass cases with black powder, BP is highly corrosive by itself, but would need the addition of moisture to become a problem before it's fired. Saltpeter, potassium nitrate, is the source of the salt, and is one of the components making up black powder, but modern powder lacks these ingredients. Brass case 7.62x54r is not that common, the communists used cheaper steel cases most of the time. Yugoslavia was the exception to this, they used a commercial grade brass case, today they are Privi Partisan, a major supplier of sporting ammunition. I believe there was some Bulgarian and I know Albanian brass case around, early, WW1 era and down Russian ammunition was also brass. Copper washed steel case 7.62x54 was a communist staple, this was especially used by the Chinese and imported by the millions of rounds back in the early 90's Later Russian imports seemed to use the green colored lacquered steel case, Yugoslavian of course was brass, and the best available from the former East block.

All the above is correct, and this nasty stuff has a name it's called verdigris.

As for the new stuff, one issue with Silver bear ammo. 7.62x54r is great, performs well, but, If you take out the rounds out of their pack, You've exposed them to air and fingers mebe. The zinc coating will start oxidizing within months, in a Mosin ammo pack, in a box, I've not tried loose in an ammo can but I will. If the're already turning white a wipe with an oily rag is the fix.