Metal re-action

[Ray P]

Good morning all. The metal re-action between a cooper bullet and the brass case neck if loaded rounds sit for say a 6 month period.
Does this bonding happen when you clean your brass in case tumbler and the case are cleaned inside and out?? Does the powder residue inside the neck cause the bonding of the bullet from not cleaning the cases? This doesn't happen with new brass or new fractory loaded brass that I have noticed.
Thanks for any replies
Later
Ray P

[Rick in Oregon]

Ray, I've got varmint and hunting rounds loaded that have been in sealed .50 cal cans for over ten years, and I never have had the condition you alude to with your ammo. No bonding whatever in the case neck if the cases are tumbled prior to loading, the case necks brushed out after neck or F/L sizing with a nylon or brass brush.

Never ever had that issue with any of my ammo. I've got some '06 LC Match ammo from 1956, and even that stuff does not have any sealant in the case necks, just the primer. No brass to copper reaction either, if there was, all military ammo would be suspect.

[acloco]

What are you treating your cleaning media with?

What case lube are you using?

What neck lube are you using?

[Ray P]

acloco/RIO Thanks for the reply. I don't clean my cases in a tumbler. I wipe em down with a shop towel check the necks for any crackes. Never thought of nylon brush inside the necks. Is the powder residue inside the necks thats causing the metal re-action?
I just checked the heads on my 6mm Remington I had loaded in Dec 09 and the snapped like a glass rod?Moved the seating about .010. Any more I prep brass with a primer and don't charge untill the week I'm going shooting.
Thanks.
Later
Ray P

[hemiallen]

Pull a bullet and shoot a picture. I doubt there is an issue.

[Fred_C_Dobbs]

Ray P, to answer your re-action question, there's two things important to understand.

1) Except for the "precious" metals (esp. gold), all metals are inherently unstable and they want to become something else that is stable. Iron, for instance, likes to become rust.

Iron, unhappy. Rust, happy.

2) Different metals tend to have different "electrode potentials." When you put two metals together that have a different EP, both metals see it as opportunity to change from what they are -- which is unstable -- to something more stable, so they swap electrons betwixt them. This very mild electric current creates a galvanic action that tends to produce corrosion where the metals are joined.

The strength of that reaction depends -- in part -- on how different their electrode potentials are. Copper has an EP of .34 volts. "Regular" brass has an EP of -.35 volts. That's a differential of only .69 volts, which is pretty low (and to be expected, since brass is partly copper). I don't know but I suspect "ammunition" brass (as opposed to "regular" brass) might be formulated knowing it'll be in prolonged contact with copper (and lead, which has an EP of -.126) and adjusted to further reduce the corrosion potential.

If the joint between them is damp or wet, the reaction gets faster. Provided it's stored in a dry place, it's unusual for enough of this galvanic action to occur between copper and brass even to be noticeable.

[Lenard]

I had an opportunity years ago to become friends with one old time shooter. He never mentioned anything about the reaction between the bullet and the case neck. However, he did explain something to me that I found to be true.

After ammunition is loaded for say 6 months or longer, the case necks will relax their hold. They do not all relax at the same rate. thus pressures will be different. Thus you will get variations in velocities beyond the norm. I doubt it would make a bit of difference in big game hunting, but certainly could with small targets.

I did some extensive testing on year old ammo and freshly loaded. Clearly, the fresh loaded ammo showed more accuracy that the older stuff. And this is using the same components.

Lenard

[Rick in Oregon]

Fred C: Thanks for a very good explanation on this subject. Very interesting, and now I'm starting to remember some of this from college metalurgy classes eons ago. Good refresher, and something to consider with older ammo.

Guess I need to shoot more and use up all my old varmint loads. Now I've got another excuse to get out and shoot more!

[Ray P]

Thanks for all the replys. I appreciated your time to answer.
The problem I've had is with fired brass, never with new brass.
So leaning toward powder fouling as my problem or "If the joint between them is damp or wet, the reaction gets faster". I can see this as my reloading room is cooler in spring time. We have steam heat so the winter the temps and humidity are maintained better.
RIO I know you said had so LC ammo stored in ammo cans and the age of that? With no problems!
Thanks
Later
Ray P

[giterdone]

Ray......You nailed it when you wrote "powder fouling as the problem" coupled with high humidity speeds up the reaction.

[OldTurtle]

Alright guys,,, Now you have me concerned about some that I've had sitting for a couple of years since it was loaded... I'm going to have to pull a couple to see the reaction..

[Ray P]

OldTurtle. Good to hear from you. This what I was tring to figure out. New factory can be loading and sit on store shelf for a couple seasons without a problem. We can load new brass and let it set without problem. Will cleaning fired brass in a tumbler and loading them and say they sit for 6 months. Will you still get a metal re-action?
Later and thanks for sharing your knowledge.
Ray P