Cold welding, bullet to case neck bonding

[Koda]

Cold "welding", bullet to case neck bonding. I came upon this subject in another forum but want to hear opinions from those I know longer here. What happens is handloads somehow bond to the case neck over time, increasing chamber pressure when firing. A common solution is to lube the bullet in graphite before seating.

A quick web search shows only a few discussions, so this is indeed a topic if somewhat obscure. I'm trying to judge just how much of a concern it is?


reloading photo for attention:

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[ma96782]

Sounds like you've answered your own question.

Concern = higher than usual pressures or maybe, the brass will tear, sending the bullet into the bore or downrange with a little something "extra" attached. Of course.....there is also that question of, "How much of a bond are we talking about"?

Aloha, Mark

 

[Koda]

Sounds like you've answered your own question.

Concern = higher than usual pressures or maybe, the brass will tear, sending the bullet into the bore or downrange with a little something "extra" attached. Of course.....there is also that question of, "How much of a bond are we talking about"?

Aloha, Mark

I guess Im still fairly new to reloading... Ive been reloading about 2 years now and this is the first Ive heard of it. I only concede its a thing, but it hasnt answered my questions. I just dont know how much, how often, or how bad it can be. Is it consistent with all handloads? Why doesnt it happen in factory ammo? I have some handloads I did last year... are they bad? Should I use graphite now on all my loads? Do people shoot old handloads with no issues?

 

[ma96782]

Usually, there is no issue IF you're just using clean brass and lead or jacketed bullets. BUT, since you said welded.......OK, that raised an eyebrow.

Maybe/perhaps/probably (I can recall).....where a guy "glued" his bullet into the case mouth to prevent "set back problems" that he was experiencing.

Whatever.
BUT, But, but......I would NOT try it.

Aloha, Mark

PS....as for your reloaded cartridges.

Assuming that you didn't "glue" them in. They look fine.

For me.....
I use a slight taper crimp with magazine fed rifle cartridges (.223 Rem, 308 W). Bolt guns could be used with only neck tension.
I roll crimp with my revolver cartridges (.38 special, .357 mag, .44 mag)
And.....
I use a slight taper crimp with my straight wall pistol cartridges (like: 9mm and 45 ACP) that will be magazine fed through a semi-auto.

 

[Koda]

Usually, there is no issue IF you're just using clean brass and lead or jacketed bullets. BUT, since you said welded.......OK, that raised an eyebrow.

Cold Welding is what Im reading as the common descriptor for this. I'm not certain its an actual welding process. I'm assuming its a chemical reaction between the copper (jacket) and the brass (case) but I don't know the cause.
Im curious now how long handloads last... whats the oldest handloads people have fired and did they work the same?

 

[ma96782]

I shot some pretty "funky lookin' surplus" in my day.

Ver·di·gris
/ˈvərdəˌɡrēs/

noun

• 1.a bright bluish-green encrustation or patina formed on copper or brass by atmospheric oxidation, consisting of basic copper carbonate.

Aloha, Mark

PS......depending on how well the ammo has been kept/stored. Yeah....the usual cool dry place is a "good start".

Then.....some countries are just terrible at storing their ammo.

 

[Certaindeaf]

I think it was with old cupronickle military slugs / cartridges?

 

[ma96782]

As for my handloads......

Yes. I've had my share of problems.
In my case.....the bullets weren't "welded".
More like, I had an issue with case necks split (.308W reloads). Because, I don't/didn't anneal the brass and the cases had been used many, many times before being stored.

Aloha, Mark

 

[thorborg]

Notwithstanding any factory screwup that should be recalled, Never seen that, of if I did, wasn't aware of it.. If I was to consider the tens of thousands of rounds I've shot, a good portion hand loaded, over my lifetime, with maybe a quarter of that old surplus stuff, I would say the concern for that happening to me, would be on the same as expectation of winning the lottery. So far I'm on par with receiving a lightning strike.
They must have been subjected to some horrifical high speed loading set up to "cold weld".

I would think something akin to rust freezing or dissimilar metal electrolysis or just plain oxidation would be more likely something worry, but those are not "cold welding" which require friction and pressure.
Some folks just need things to worry about.
small example of cold weld:
I used ultrasonic vibrations, and pressure, to cold weld copper wire connections to silicon transistor chips for the making of high current transistors used in military's VRC 12 radio.
The Ultrasonic welder in this case, was called a "ball bonder".

 

[Greenbug]

Not really an issue for the average plinker/shooter/hunter.
If you are an F-class/Benchrest/PRS shooter then, yes it matters and can affect velocity SD's and extreme spreads therefore affecting long range consistency/precision. I hear the F-class and PRS guys will load their cartridges long and seat to length just before the match, benchrest guys just load between relays.

 

[Certaindeaf]

Not really an issue for the average plinker/shooter/hunter.
If you are an F-class/Benchrest/PRS shooter then, yes it matters and can affect velocity SD's and extreme spreads therefore affecting long range consistency/precision. I hear the F-class and PRS guys will load their cartridges long and seat to length just before the match, benchrest guys just load between relays.

Probably has more to do with atomic bonding on a miniscule level but it would help consistency, however theoretical.

 

[dangerranger60]

I have spent a lot of time welding and soldering copper to brass fittings, and nearly 50 years of reloading. I have never heard of cold welding being a thing.
Hot welding takes a lot of heat or a lot of pressure. Cold welding would take a chemical reaction that would also change the powder and primer.
so unless you are purposely gluing the bullets in place I would not worry about it even being a possibility. DR

 

[oremike]

I know way a long time ago you could find 30-06 ball ammo that was sealed with some sort of asphalt and that stuff shot fine.

 

[ma96782]

That black sealer on the bullets of military ammo is common. It helps to keep the ammo water proof or maybe just more resistant to water entry. Like the sealer on the primers.

Then.....
Yup.....I can remember the advice to "break that sealer bond" (for more accuracy) by running the ammo through a seating die with the bullet plug just a bit lower than usual. It was said to improve the accuracy of the ammo. Course.....I heard that done with those old military match ammo.

Not to mention, making up some Mexican Match Ammo.

I figure that, most shooters probably didn't care all too much with the sealant on their surplus "ball ammo/rounds".

Aloha, Mark

 

[Local Loader]

Cold Welding is what Im reading as the common descriptor for this. I'm not certain its an actual welding process. I'm assuming its a chemical reaction between the copper (jacket) and the brass (case) but I don't know the cause.
Im curious now how long handloads last... whats the oldest handloads people have fired and did they work the same?

So cold welding is a thing but it's not very common. In aerospace, cold welding is actually a really big concern as it can cause parts to fuse together that they don't want to. There are also tools for doing cold welding but their not really ment for large scale or thick metals. But not all cold welding equipment is actually cold welding, it actually does a standard welding seam but cools faster since it's a thin shallow seam.

 

[Koda]

So cold welding is a thing but it's not very common.

in reloading?
It sounds like its random, it "can" happen and for those it has happened probably are the ones that graphite lube their bullets when seating.

 

[Local Loader]

in reloading?
It sounds like its random, it "can" happen and for those it has happened probably are the ones that graphite lube their bullets when seating.

For cold welding to happen on its own, the two metals would have to be free of contaminates between them. I think the more likely cause is that someone used sealant and forgot about it.
Graphite shouldn't in theory cause anything to weld over time, another guess would be the bullet got hot enough that some of the lead melted and caused it to seal like with copper pipes.
Unless you're sandpapering your cases and bullets I wouldn't worry about it.

 

[drstrangelove]

I dip my case necks in imperial sizing wax before resizing so the football is less likely to pull up the shoulder on the outdraw. Makes for a uniform neck tension, hasn't hurt my velocities or groups any, and I know if I need to pull a bullet that it's coming out.

 

[Local Loader]

in reloading?
It sounds like its random, it "can" happen and for those it has happened probably are the ones that graphite lube their bullets when seating.

https://interestingengineering.com/innovation/cold-welding-joining-metals-without-heat a decent article and wiki doesn't seem to do a bad just at explaining it either for once.

 

[Koda]

For cold welding to happen on its own, the two metals would have to be free of contaminates between them. I think the more likely cause is that someone used sealant and forgot about it.
Graphite shouldn't in theory cause anything to weld over time, another guess would be the bullet got hot enough that some of the lead melted and caused it to seal like with copper pipes.
Unless you're sandpapering your cases and bullets I wouldn't worry about it.

I havent read of anyone using a sealant (Im aware that some milsurp ammo uses it).

Most reloaders clean their brass so I would think most handloads the metals are free of conaminates between them. Its an obscure topic though and so far the consensus here is nobodys experienced this phenomenon, yet.