Corrosion on handloads==> dissimilar metals reaction??

[DIBBS]

I was recently given some 7mm mag handloads from an estate. Some are loaded in nickle plated cases, and show blue green corrosion @ the case neck. Is this possibly due to a "dissimilar metal" reaction between the copper bullet jacket and the plated cases? I plan to pull the bullets and see what the powder looks like...probably fertilize the flower bed. Has anyone seen this on ammo of "relatively" recent manufacture/

 

[gunsnjeeps]

I haven't loaded nickle cases but most of my carry ammo seems to be in nickle cases. I've seen the bullet lose its shine from oxidizing but not corrosion. Is it hunting ammo that someone may have carried in the field and exposd to dew or rain? I also have a knife, Case I think, that gets a greasy green corrosion on it if you leave it in the leather sheath. Leather ammo wallet maybe?

 

[bigedp51]

DIBBS

It is a form of "dissimilar metal corrosion" and it happens with all loaded rounds, brass contains zink which can in turn bond to another surface. Benchrest shooters and accuracy nuts do not like to wet tumble their cases with stainless steel media because the inside of the case necks are too clean and the bullet can "bond" to the case neck. These shooters prefer to leave the inside of the neck with a carbon coating to ensure equal bullet release force and no bullet bonding. What you see is the same thing as a galvanized chain link fence used to prevent rust on steel fencing through the transfer of zink atoms to the steel. The only difference is what you see is Zinc oxide as the zink also reacts with oxygen and moisture.

 

[lancetkenyon]

I would say moisture too.

My future son-in-law got a .308 from his father with a lot of old hand loads. A few of them had some green/turquoise crap around the bullet/case neck. We pulled everything apart to clean and reload with fresh components and I was amazed at the amount of rounds that were corroded inside. Some of the powder was caked and stuck to bullets/primer pockets/cases, etc., and a lot of internal green corrosion. They came out of Washington state. Here in AZ, we don't usually have this problem. Also, I shoot enough to not allow time for the corrosion. A good way to prevent this issue!

 

[DIBBS]

Thanks for the feedback. I've never liked plated cases for rifles, although I do use them some for pistolas. It is the blue-green turquoise crap around the case neck. I've been unsuccesfully trying to put some venison in the freezer, but will eventually pull them sometime this fall-winter and report back what crap is inside of the cases. They came from SE USA, not sure if they were carried in leather or exposed to moisture.

 

[former naval person]

Whatever you find...don't shoot other people's handloads.