Bullet cold weld to brass, real or myth?

If this is happening it sure doesn't seem to be an issue. I have ammo that I loaded years prior and occasionally use without issue.
Virtually every box of factory ammo is more then 3 months out from manufacture and most sits in warehouses or on the shelves for MUCH longer.
I have friends that don't reload. They typically buy a new rifle and enough ammo to last them through several hunting seasons.
And then there is that military ammo in .223, 308, 30-06 and so on that has been laying around for a decade or more.
A lot of factory ammo & military ammo is crimped or has a lot of neck "grip" to begin with. The increased tension/grip of "cold welded" factory ammo may not be close to the difference that we notice in our handloaded stuff when it "cold welds". My dad shot 13 deer from the same box of 30-30 win silvertips over a period of 23 years. He died at 92 two months ago.
I believe there is still 2 in that box. Not long range, never chrono-ed, they were crimped and I bet there was cold welding.
It won't make a difference in short range stuff. But most LRH ammo required consistency in all aspects.
IMHO,
Randy
 
If the mechanism is galvanic corrosion then ambient moisture is what drives the process. Two dissimilar metals in 100% dry contact will not galvanically corrode. Add .05% relative humidity and the process starts.
Looking at this table: http://www.designbyinitiative.com/files/8514/2711/8760/Galvanic_Table.pdf the galvanic potential between yellow brass and some Cupro-nickels is only about .2 eV, but to others it is about .4eV. I would not expect much activity from the first group, but I would from the second group.
 
I believe this can certainly happen. How long it takes I don't have a clue.

IMO-this is only an issue for those looking for the utmost in accuracy from handloads. The guy that's looking for SD's in the single digits. And for those loading it's only an issue if you're using bushing dies to reduce neck tension on the bullets.

For the average handloader using standard RCBS or similar or the guy shooting factory ammo, I feel like neck tension is high enough to make the cold weld virtually un-noticeable.

JMHO...
 
It would appear some of the thread is missing such as the OP's response that he will look into HBN in another post.

There are plenty of long threads on this site as well

How to, HBN Hex Boron Nitride Coat Your Bullets and Rifle Barrel



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How to, HBN Hex Boron Nitride Coat Your Bullets and Rifle Barrel
In this instructional video Jeff Brozovich shows how he applies HBN to his bullets and rifle barrels. #BergerBul...






hBN bore treatment?



hBN bore treatment?
Don't bother with media in a vibratory tumbler.
 
I been reloading for over 30 years and probably have some rounds that I made 20 years ago. Never had an issue with this until this week. I had some 6.5-300 wby rounds that I made 6 months ago. I made them right at max length for my rifle. Shot some and the accuracy wasn't that great. Still doing load development for it. So I decided to reseat the remaining rounds a little shorter. Worked great except for one round. It actually collapsed the case neck instead of seating the bullet deeper. Got to be a little more careful to ensure I get some lube in the necks!
 
Only had it happen to me when my cartridges got wet from snow. The they welded almost instantaneous. It was bad, almost blew up my gun

That's interesting, I've dropped cartridges in snow before and never observed this, but I do believe you. Odd stuff.

I wonder if factory ammo has a bit of oil or something on the bullets or cases?

I've shot .270, 30-30, and 308 ammo from the early 70s and didn't notice anything overpressure, even pulled a few of the .308s and it didn't seem especially difficult.

IN fact I've never heard of factory ammo doing this but I have indeed read of handloaded ammo doing this from a few sources.

Perhaps the factory ammo is loaded in a more climate controlled environment as in 0 humidity. That would affect things.

Lastly, perhaps it only seems to be a handloaders problem because factory ammo has to be loaded lighter as it needs to be safe in firearms of varying tolerances, cleanliness, action types and strengths, ages, in all temperatures etc.
 
I frankly never heard of this before just now. But I think this may have answered a question that I've had pondered over for about 20 years.

In 1996 I shot in a police sniper match with my Win Mod 70 heavy varmint rifle that I personally owned and carried in the trunk of my patrol car for years. The department would not pay for my ammo but at least they paid my entry fees and lodging etc. It was a 2 day match and required about 200 rds of ammo of which we shot about 125. I did have about 20 boxes of LC white box match 173 gr FMJBT 7.62x51, dated 1972, so I used that. The rules specifically said no reloaded ammo, factory only. My ammo was older than most of the competitors. As a Sheriff's deputy in those days, we had to pay for our own ammo and weapons.

In the early 80's I was in the National Guard and we were issued ammo can after ammo can of the white box 173 stuff to use for practice in competition M14's. For serious matches we pulled the FMJ bullets and reseated Sierra 168 HPBT match. The improved accuracy was noticeable and we thought it was worth 5% or so higher scores, especially in the 600 yd slow fire prone phase of the qualification match. (same match as the NRA HP) We called this improved round Mexican Match.

As I think about this cold weld business, what we did to the LC ammo was pull the original bullet (173's) thus break any cold weld, then reseat a new bullet. And then shot that newly seated round in much less than 3 months. Thus there was no, new cold weld... or so I now think.

In the Police match mentioned above, I had several "flyers" that were high or low but not so much any problems with wind. I just chalked that up to the fact that I was older and did not have the opportunity to practice as much as I did in the military.

I have been retired from the S.O. for nearly 9 years. I still own that rifle and I now still use that LC 72 date brass but I load it with Horn 168 gr AMAX bullets. It shoots better now that it ever did with any match factory round. One odd thing about that rifle is that it seems to weigh a lot more these days than it did back then. But carrying it 50 feet or so from the pickup to the shooting bench at our range, and setting in up on a rest is still well within my capability. I have a much lighter but very accurate Browning A bolt stalker that likes the same ammo. It will reach out and bag any antelope or deer I'm likely to shoot. And that decision is made much less on how far I can hit it, as it is on how far I am willing to drag it back to the truck.

Thank you Dartonjagger for starting this thread. I think I learned something.
 
HBN coated bullets seems to help with this, I try to leave some carbon in the neck(no longer SS tumble or ultrasonic) and sometimes Q-tip the case neck with Imperial wax and I seem to get more uniform bullets seating pressures. Uncoated bullets and ultrasonic cleaned brass had very uneven seating pressures. Yes I have seen some very stuck bullets as I used to shoot a lot of military surplus ammo.
I don,t know about the newer military ammo but the old stuff was sealed with shellac. Primers and bullets. I don,t know but I wonder what pressure it takes for the neck to expand away from the bullet? I have never seen this and I have shot ammo I had loaded years before. But I always get some Hornady one shot inside the necks too when I resize. Like a 270 Winchester. Bugger to size if you do not get some lube in the necks.
 
I don,t know about the newer military ammo but the old stuff was sealed with shellac. Primers and bullets. I don,t know but I wonder what pressure it takes for the neck to expand away from the bullet? I have never seen this and I have shot ammo I had loaded years before. But I always get some Hornady one shot inside the necks too when I resize. Like a 270 Winchester. Bugger to size if you do not get some lube in the necks.
If you run the ballistics you'll see it really doesn't show up until ~800 yards which I doubt anyone would be shooting mil surplus ammo at that distance. For example my 6.5x.284 with a 140 at 3,000 fps and at 3,100 fps(increased velocity from bonding to case) the difference is ~7" at 700 yards, 11" at 800 yards, 15" at 900 yards, etc.
 
If you run the ballistics you'll see it really doesn't show up until ~800 yards which I doubt anyone would be shooting mil surplus ammo at that distance. For example my 6.5x.284 with a 140 at 3,000 fps and at 3,100 fps(increased velocity from bonding to case) the difference is ~7" at 700 yards, 11" at 800 yards, 15" at 900 yards, etc.
Thanks and good to know.
 
When I load I always load to the top. Not too hot but max as fast as it will shoot well but not expand the brass. But I have never seen an ejector mark on stuff I had loaded for a long time.
The worst I have seen is Winchester brass that split the necks in storage and that was new unfired brass.
 
I been reloading for over 30 years and probably have some rounds that I made 20 years ago. Never had an issue with this until this week. I had some 6.5-300 wby rounds that I made 6 months ago. I made them right at max length for my rifle. Shot some and the accuracy wasn't that great. Still doing load development for it. So I decided to reseat the remaining rounds a little shorter. Worked great except for one round. It actually collapsed the case neck instead of seating the bullet deeper. Got to be a little more careful to ensure I get some lube in the necks!
Can I ask what bullets you were using?
 
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