Cold bonding of plated ammo.Read this.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

DRC458

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Mar 1, 2006
Messages
11,530
Reaction score
10,888
Location
Enid, OK.
Yeah, thanks for posting. I never even think about that. I've got some ammo that's been loaded for years. Now, it kinda' concerns me. Like somebody in that thread said, ' Thanks for giving me something else to worry about!' I haven't loaded many plated bullets, but I do have some on the shelf.
 

swampratt

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Nov 3, 2010
Messages
12,720
Reaction score
19,275
Location
yukon ok
I think it is like galvanic corrosion.
You have dissimilar metals together and they basically weld to each other. Street terms forgive me if I botched up the explanation.
 

DRC458

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Mar 1, 2006
Messages
11,530
Reaction score
10,888
Location
Enid, OK.
I think that's a reasonable laymen's terms explanation. It simply means (to me) that a bond is created between the bullet and the case that leads to having to break that bond before the bullet leaves the case upon firing. So, it could increase pressure among other things, like weakening the case.
 

Blitzfike

Sharpshooter
Special Hen
Joined
Aug 16, 2006
Messages
2,096
Reaction score
10
Location
Tuttle, OK
The only problem I have had with plated bullets is the wrinkling of the plating when neck tension is too tight. I had one blow out the magazine in a Taurus PT945 and all I could find was the possibility that the plating caused the gun to fire slightly out of battery. Didn't hurt the gun, but destroyed the mag and my pinkie finger on the off hand was swollen and had nerve issues for several months. I tore down all the remaining bullets and they were all spot on with charge weight. I chalked it up to wrinkling of the plating. Now I need to look more into this cold bonding situation. A friend blew the top of the chamber out of a Taurus PT-96 (40 cal) with plated bullets and we couldn't find any overcharges in any of the remaining rounds. I have reloads that are 12 to 15 years old, both rifle and pistol with standard jacketed bullets and have never had an issue with any of them.
 

swampratt

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Nov 3, 2010
Messages
12,720
Reaction score
19,275
Location
yukon ok
I brush my case necks out a couple times during rifle case prep. probably removes any foreign matter that could possibly accelerate this phenomenon.
A mystery for sure.. Could even be oily fingers or acidic fingers handling the bullet.

My hands are dry , my wife's hands are always clammy. My buddy on lot's of meds hands are acidic .. he can touch his model 94 bluing and less than a week later rust is forming.
I noticed this 2 years ago ..I cleaned both mine and his model 94's and no rust on mine and his had rust in finger hold shape..That is the only thing we could come up with as to why his will rust quickly.

Now he wipes it down very well with a clean cloth after handling it.
 

dennishoddy

Sharpshooter
Supporting Member
Special Hen Supporter
Joined
Dec 9, 2008
Messages
84,556
Reaction score
61,836
Location
Ponca City Ok
I spent about an hour looking up and reading links about cold bonding on the internet this morning.

Cold bonding/cold welding is when the electrons of similar metals meet and blend, creating a union. Cold welding is done a lot in aircraft from what I read, but has to be performed in a vacuum. Tools used in space, have a special coating, because if they don't, they will immediately weld to the metal they touch. This is just kind of an overview of what I read. The links go into great detail with a lot of scientific reasoning that is beyond me, but That's what I got out of it.

Since these rounds were not subjected to a vacuum, I'm curious what really happened. I've seen two plates of steel with an oil film between them become almost glued together after they have sat in that position for awhile. The steel bars in our rack at work would have a coating from the factory, and when stacked, it took a prybar to separate them at times.
I don't shoot a lot of plated rounds, but have some jacketed that is 20+ years old and shoots just fine in rifle and pistol. I have some old milsurp .45ACP steel case that you can't pull the bullet with a collet puller, because of the varnish, but they shoot fine.

Bottom line, I don't know what caused it, just throwing some more info out there.
 

Latest posts

Top Bottom