[ScottD]

I received my starter tabs (from a fellow forum member) and I dug into my ammo stash to add them to some belts. I opened a can of surplus 308 that I linked about 3 years back (now separated into 10 round sections per NY law, of course) and most all the cases were heavily tarnished. The ammo is South African, 1982 if I remember correctly. I dont know WHAT I did to it when I linked it, but some of the ammo is just NASTY. I threw 50 rounds into a tumbler tonight with coarse walnut media....lets hope it cleans up. I DONT want to waste this stuff at .50 a round, especially seeing how its non re loadable. (Berdan primed)

What the hell causes tarnish/corrosion like this? (I broke down the *worst* of all 100 cases, the tarnish is all on the exterior) The only thing I can think of was I used a rag with some WD40 to wipe off the links and dog hair from the ammo.....???(very light, I know oil will kill primers...but a light wipe on the case exterior???)

 

[xdevildog]

Bi-metallic corrosion? Possibly a reaction between the steel in the links or leftover chemicals from coating or bluing the links and the brass cases - facilitated by the light wipe of WD40? My experience is with aircraft, but I'm only guessing when it comes to ammo. Any forensic metallurgists in the crowd?

 

[SlugCatcher]

never a waste even if you can just salvage the bullet.

 

[ScottD]

I tumbled the worst 50 rounds overnight. Most of it came clean, but there are a few other spots I need to keep my eye on. Ive never seen random corrosion like this on ammo before. So far it all seems to be on the surface with no pitting, but it took some 1000 grit sand paper to remove some of the darkest spots. As this ammo is berdan primed, I cant even reload it. Im going to clean it all up and store it with extra dessicant and check it again in a few months.

 

[OldSoldier]

Yesterday I shot a bunch of RG 42 in my Bren that was slightly dirty and had an occasional spot of corrosion. It fired flawlessly and was amazingly accurate hitting a 12x12 inch steel target consistently at 300 yards. I hate to admit that the Bren with crappy looking 73 year old ammo had more consistent hits than my M1A with shiny new gov't contract ammo.

 

[mt-ac]

Cleaning corrosion

You can also use a weak solution of oxalic acid. It is found in many cleaners such as Barkeepers Friend, try Lowes. When trying to kill primers it is not as easy as most think. I pulled down thousands of rounds of IMI 5.56, washed the brass in Iosso case cleaner, rinsed in water, and then tumbled to a bright shine using Iosso again. Primers dead right? Wrong! Did tests in hundred round lots, 95-99 percent fired. Finally just reloaded and shot it.
As suggested the corrosion is most likely from the reaction between different types of metals with oil helping. There should be information in the Machinists book about this.

 

[Finalygotabeltfed]

A picture of the corrosion would be helpful.

How much was the ammo handled during linking and by whom? Some people have extremely corrosive perspiration from their hands and it will corrode metals in a very short time. This is why when ever someone handles my guns, I wipe them down before storing them away.

If the ammo is corroded around the link contact point, it is galvanic corrosion due to dissimilar metals in contact and moisture.

Don't be too anal about cleaning the stuff, they don't have to be spotless to shoot them. Imagine the contamination long term in the field?

 

[CDTX2001]

I bought a bunch of that Pakistani surplus a couple years ago, lots of the rounds had some corrosion on them. Never cleaned them and ran them through an AR-10 without any problems.

 

[ABCB]

I bought a bunch of that Pakistani surplus a couple years ago, lots of the rounds had some corrosion on them. Never cleaned them and ran them through an AR-10 without any problems.

Same here, only with IMI 5.56x45 ammo. I picked up 1k rounds at a local flea mkt. for less than .10 a round. This stuff looked like pure s#$t, BUT, I haven't had a FTF yet..... I even ran some of it through a home built AR with a bump-fire stock this wknd, and 30 rnd mag dumps weren't a problem!

Thanks KevinT!!!