...that is a bullet bonding to the cartridge case over time. Eg:I decided to run some Hornady SST'S and GMX'S through my hunting rifle and found the loads showed signs of high pressure,tougher than normal extraction and catering primers and these were from the same lot of loads exactly. So I returned to my bench to find out why and pulled bullets with great effort and seated some deeper and heard a click.
Of course then I started to do some reading about this and is a real thing.I was using Hornady brass, and all other components checked out to.
I have put this info out there and have told all kinds of things and some disbelieving me.So ,What have you experienced?( I don't tumble clean and wipe out necks of Hornady sizing wax ) Tony

I had a couple of cases that were hard to extract at Quemado last year, and they were loads that I had been using for years. I just pulled some out of the 100 round container at random and shot them, as they were all the same loads. Might have been the problem. miles

It happens. Since I was able to start storing my bulk ammo in climate controlled, I've not really had an issue.

Before that 1000s of rounds would sit in the loading room in our TX heat and if not shot the year or two after loading would often cold weld a few adn or split necks badly.

I did start annealing necks if KNEW it would take some years before I might shoot it.

Wouldn't bumping the seating depth a little bit take care of the cold welds? It sure helped with the asphalt sealed necks on a bunch of Lake City M118 & M852 ammo a friend had.

Somewhere I've read of a serious shooter who deliberately loaded his cartridges long if they weren't to be used right away. He'd seat to the correct depth before going to a match.

Yep, seating bullets slightly deeper is an easy way to break the bond.

Another way to prevent it is not clean brass unless necessary, and it rarely is. Aside from wiping off cases that fall on the ground, I rarely clean 'em. The inside of the necks gets a light brushing, but not enough to remove the last light layer of powder-fouling. I haven't had a problem with cold-welding in many years.

I was surprised to see how much effort it took to break this bond with a
.277 caliber bullet
Next question- larger bullets have greater contact due to a larger surface are between bullet and cartridge case/neck. With a 45/70, has this bonding process ever caused failure with a firearm?
I am also a 45/70 user and ocassionally I here of rifle failures and it seems a mystery. Just wondering folks...Tony

I like reading you more and more

John,

Just to clarify, are you saying you don't clean the necks by tumbling? I put mine in for a fairly short while and the insides still look pretty dark.

I have never seen an issue in the 45-70. But I would point out that, while the surface area is somewhat greater, (depending on the bearing length of the bullet), it is actually less in the larger diameters relative to the surface area of the bullet's base so that plays into it I would imagine. I know that when interia-pulling bullets from loaded ammo, I'd much rather pound 300s out of 45-70 cases than 140s out of 6.5 Swede cases; the former being some of the easiest to pull, while the latter are some of the most difficult. (Of course, unlike with standard ignition bullet removal, interia pulling has nothing to do with bullet diameter.)

SOTG,

I don't clean brass at all by tumbling, unless absolutely forced to for some reason.

Dunno if tumbling "for a fairly short while" would prevent cold-welding or not.

I can't help but wonder if sometimes the cleaning additives we put in our tumbling media doesn't leave a layer behind and then become a problem between the brass and the bullet later on. I always check older ammo by seating deeper before heading to the range.... sometimes it's there and sometimes not.....I've seen the less of it with Hornady bullets for some reason.

I quit putting any additives at all in my walnut shell media, and I'm rarely tumbling them anymore anyway.

I don't know if weld bonding was my trouble, but I don't tumble cases with or without cleaning additives. I do run a brush through the necks, in and out a couple of times. miles

I have a one pound can of HBN and have been lubing the inside of my case necks with it using a nylon brush to (maybe) keep the cold weld thing at bay and to help with a uniform bullet seat and release.
Does it work? I have no idea. But I do it anyway.

Thank you, sir.

I've read the same. Don't know if it's the same source, but it's a good idea.

In all my years of loading/shooting/hunting it has only happened to me 1 X.
They were 06 loads that had been loaded more than 2 yrs.

It is real as is evident from the responses here.

Jerry

Is the problem happening with new brass also or is it only after tumbling used brass?
If the cleaning process by tumbling is causing this issue. Would setting the brass aside after tumbling for a week or so before reloading cure this problem?

Tumbling has never gotten the insides of case necks really clean for me, even with nut shells and added cleaner. Maybe ceramic would. Usually, my cleaning consists of wiping them off with a rag to get any grit off.

When I FLS, I dip the necks in powdered mica or lately one of the little tubs full of powdered lube and beads. That ought to be enough contamination to stop cold welding.

And a very hearty "Thank You!" from here as well.

Wasn't Weld Bonding the wagon master on "Wagon Train"?

I'm reloading ignorant so let me exploit my ignorance a bit and ask, is Weld Bonding an issue with Factory ammo? this is the first i've read about it and find it interesting to say the least.

Yes

I used the "contact us" feature on one of the ammo manufacturers' website to ask how they deal with the issue. The response I got was the equivalent of a blank stare. This left me with the impression that it's not something they want to acknowledge or discuss.

Somebody gave me a box of really old Federal 270 wins.
Was a lot of "green" around the bullets and case mouths. I figured these shells had gone through a lot of heating, cooling, and moisture associated with many seasons of Being in pickup trucks, cabins, and out in the woods....

For fun i thought I would pull one down and I was pretty surprised.... no signs of bonding and everything from the case mouth down the inside looked pretty much pristine.

Just reporting what I saw...

I also never tumble, unless absolutely necessary. I just brush necks lightly with nylon brush , wipe off grit. Lightly clean primer pockets and load. I never had issues with Cold weld. I am also lazy so in this case it has helped me........

I believe he was, but I think his name was Weld Bond.

Thanks for getting it - great show.

Today I decided to pull bullets on loads of various ages! I pulled 8x57 loaded in 86, 22-250 from 78, 30-06 mil from 52, 243 from 99, 308 from 2014, and 338 from 2011. I pulled three of each caliber! The cases all looked great on the inside, with no signs of bonding! All were loads from my bench with the exception of the 30-06. I do tumble before loading but I don't do anything to the neck for hunting loads. Just size trim to length, deburr, and load! Maybe the necks are contaminated enough that bonding is not a problem! So what did I accomplish today, nothing except entertainment! To those with bonding issues, what was used to clean the necks? The bonding sounds like some sort of electrolysis! Am I off base here? This thread has really intrigued me because I had never heard of this weld bonding before this thread! I've been reloading since 1962 and it's never come up, in my circle of reloading friends! Of course none of my group are ammo scholars, just gun nuts!

Heym

IMO it's more commonly called Cold Weld. Unless I'm mistaken and I'm pretty sure we discussed it last year, maybe not on this forum.

Last year was my first experience with cold weld. I had some 06 loads from a couple of years back. It's a load I've used a lot in the past. But I had a couple of shots where there was difficult bolt extraction. I stopped immediately and then seated the other loaded rounds deeper. There was an audible pop/crack. I reseated the bullets again and had NO problems.I normally don't clean inside necks 'other' than swab lightly with a clean Q tip.

If you're interested enuff you might search cold weld here in Ask the Gunwriters or in Hunting Rifle forum. Good luck.

Jerry

. I will do some research on line. I'm going to dig out my books on metallurgy from college and look at brass and copper composition! Just seems strange that it only happens randomly! I'm going to take a larger sample base and see if that changes the statistics I've seen.

I believe this is the thread jwall is referring to:


http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/6981105/1

I wonder if acidic oils in fingerprints promote cold weld. One of my buds at work is one of those unfortunates who has to wipe all fingerprints off a firearm before putting it away, otherwise corrosion sets in and permanently etches fingerprints into the finish. I don't have that problem myself, fortunately and I wash my hands before handling components anyway, but I wonder if there's a correlation.

I have a little bit of that problem, but not quite that bad. I also have a lot of static electricity. I have problems with the wrappers on crackers like you get at a restaurant, or small candy. Can't put them down, they just stick like glue. miles

Miles,

Your magnetic personality could be part of your problem there! (chuckle).

miles

It seems to be a question which comes up regularly.

The mechanism by which it occurs is diffusion: where you have two similar metals in intimate contact, with nothing between them, atoms from one can diffuse into the other, and vice versa, across the interface. Essentially they wander about and forget where they are supposed to be, until enough of them have migrated that the boundary between the the bullet and case neck is blurred, and you have a joint.

Diffusion bonding, the usual name, has some industrial applications too, especially when you want to weld really delicate or thin materials where any heating, such as is used in conventional welding, would be impracticable. I remember doing some work on just such an application many years ago, involving a miniature heat exchanger made by diffusion bonding of very thin corrugated sheets together to make a honeycomb.

If there's something between the two surfaces, it can prevent the wandering atoms from crossing the line. Something like wax for example would have such an effect. Or, as MD and I have independently found, not bothering to tumble cases and relying on grottiness seems to work too.

Would spraying the bullets with Hornady OneShot, then allowing to dry before loading, work to prevent bonding without any adverse effects?

I inside lube with graphite. That should help, probably not a reliable cure though.

Thanks for that explanation, best one I've heard yet. I'd always assumed it was a galvanic thing, but diffusion makes perfect sense. That's something that also takes place between copper and tin/lead alloys when electronic components are soldered onto circuit boards.

I've been using Imperial Application Media with dry neck lube for a while with the thought in mind that whatever causes cold weld, maybe the neck lube would help interfere with the reaction. I'm not sure any of the ammo I've ever reloaded developed cold weld in the first place but prevention is a good thing, I think.

I use Imperial dry neck lube as well and only tumble clean the brass when I have to.

I've wondered about the guys that use a bronze brush to remove the powder residue inside the case neck but I don't bother so I won't find out for myself.

"Pick your battles" and "Don't make unnecessary work for yourself" come to mind.

I've been reading about this in my spare time for a couple days! I believe it caused by case necks being undersized for the bullet. Along with case shrink over time! Since new brass seems to be resistant,annealed brass is more resistant, than used not annealed brass! Dirt and residue acts like a release agent. Bench rest shooters have many theory's. Since I have never experienced weld bonding, I'll accept the little knowledge I've gained, and call it good! It's just not that interesting any longer!

Or maybe this one:

http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/10971158/1

.
I seem to recall reading that "secondary seating" was an old trick used by shooters that loaded in large batches. Consequently some of that ammo may sit on the shelf for quite awhile.

I've found some ammo that has been sitting for years on my shelves to be almost impossible to pull bullets using an RCBS collet die puller but when seated just a tad deeper they pulled normally.

Bench rest shooters are commonly seen carrying a tray of primed cases at the range for this reason. Any incidence of weld bond will/can change accuracy as the release on the bullet cannot be uniform or reliable.

Good information on this issue from everyone and it will change how I do things in the future.
I put this issue out there with our locals and the feedback was poor or disbelief.
Recently my safe hunting loads became over pressure and pulling bullets was a chore, so I knew something was up. I kept a few as they were,seated a few a touch deeper and pulled and weighed the rest.I will chronograph these as well...
Tony

Yes this is it and the last one I remember discussing. I searched 'cold weld' and didn't find what I was looking for.

Thanx

Jerry

In Corrosion Control classes they told us similar metals in contact cold weld because, in the case of bullet and case, the copper atoms in the bullet don't know they aren't the same as the copper atoms in the case, so they adhere at an atomic level, sharing electrons. Or so the Chief teaching the class said.
There is also galvanic corrosion, or welding together through electrical micro-voltage process which could be enhanced or encouraged by residual case lubes or cleaning detergents.
But, I don't know for sure. Never studied it in cartridges.
_________________________

Now we're cookin' !

......the presence of Zinc (in solution) in the cartridge brass actually leads to / contributes to galvanic transfer, IIRC.

GTC

This is very similar to what Pappy posted last year in the Sticky Bullet Syndrome thread.

"Pappy348 Offline
Campfire Tracker

I did find this on Wiki under "cold welding":

"The reason for this unexpected behavior is that when the atoms in contact are all of the same kind, there is no way for the atoms to “know” that they are in different pieces of copper. When there are other atoms, in the oxides and greases and more complicated thin surface layers of contaminants in between, the atoms “know” when they are not on the same part."

— Richard Feynman, The Feynman Lectures, 12–2 Friction

Thanks, John.
Edited by Pappy348 (02/18/16)"
_____


These things certainly sound reasonable. I just know from my limited experience with 'cold weld', I know what I used and what I didn't, and I know that powder 'Temp Sensitivity' was NOT the cause.

Plus, after breaking the seal (weld)--the same--loads did not exhibit the xtra pressure signs.

Jerry