Cold welding of bullets in case necks and moly coated bullets

[jackbrownii]

Does the "cold welding" phenomenon that's been discussed around here seem to raise its head if you're loading moly coated bullets into cartridges that end up sitting around for a while?

Thanks.

 

[jonbearman]

I cant wait to see any answers related to this.

 

[Terry]

My experience is that moly coating prevents cold welding.

 

[LHSmith]

Depends on how well the coating bonded to the bullets. Way back, I seem to remember a Daily Bulletin article which in some instances it was determined the moly was scraped off the bullet as it entered the neck.

 

[bigstick6017555]

just this last summer I found 40 rounds of 219 zipper that I had loaded some 30 yrs ago. out side, a little oxidation on case and bullet. slightly cleaned them and took to range and shot all 40 no problem. poi was different because of different bullet mfg. as far as grouping, I saw no difference in this ammo or recent ammo I loaded for it. shot out of a lever gun at 100 yds.

 

[Terry]

Depends on how well the coating bonded to the bullets. Way back, I seem to remember a Daily Bulletin article which in some instances it was determined the moly was scraped off the bullet as it entered the neck.

Using a standard and steeper angle chamfer tool helps prevent this.

 

[weewilly]

This does happen with moly coating bullets left for several years. Had a friend shooting a 222 that he had loaded moly bullets for after they set around for about 3 years, and the first 3 were not noticed as being any different from when they were loaded, 4th made louder sound and the primer pocket was enlarged with primer falling out when he removed the case. He had shot a bunch of these before and decided to shoot this rifle since he hadn't shot it for a while. He pulled the bullets and they were stuck to the cases. He told me about this and I had a bunch of 22-250 that had been loaded about three years, so I ran them back through the seater die and each and everyone popped when moved. I then shot them without any problems.

 

[jackbrownii]

Thank-you, gents. Seems to be a little mixed, like many things in this hobby. ;D

 

[jr600yd]

Me thinks it has more to do with HOW the ammo was stored not how it was made?

 

[AckleymanII]

I stored mine in case guard ammo boxes and it happened

 

[Dans40X]

Either coated or naked-

Your neck tension will determine "IF" you weld jackets to your brass or not.

 

[Warren Dean]

I cant wait to see any answers related to this.

Ditto....

 

[jackbrownii]

Either coated or naked-

Your neck tension will determine "IF" you weld jackets to your brass or not.

Interesting. I had not seen that theory posted before in the cold weld threads I've read. Have others seen this correlation?

 

[Dans40X]

No theory involved..... it's a fact.

Load Dummy Naked or Coated bullets into annealed brass-
Seat bullet of choice into a neck w/ .002" neck clearance/press fit.
Seat bullet of choice into a neck w/ .003" neck clearance/press fit.
Same as above w/ .004" neck clearance/press fit.

Leave undisturbed for 48 hours.

With indicated equipment,re-insert dummy rounds into seating die & seat bullets .010" deeper into case & measure force required to BREAK bullets loose.

Pull bullets w/ collet type puller-
When there is any dis-colorization/scratches/galling in bullet jacket cold welding has occurred.

 

[Brians356]

Depends on how well the coating bonded to the bullets. Way back, I seem to remember a Daily Bulletin article which in some instances it was determined the moly was scraped off the bullet as it entered the neck.

Using a standard and steeper angle chamfer tool helps prevent this.

Even better is to burnish the case mouth with 0000 steel wool. And so easy, too.

 

[Brians356]

Is "cold welding" like "cold fusion"?

 

[midnightsunfun]

I got a couple of boxes of factory ammo with a Steyr Mannlicher .22-.250 a few years ago. The ammo boxes and cases all looked just fine, but firing them split the necks on at least half of them, so I discarded all the brass. I unloaded the second box, and the bullets all had black discoloration on them where they were in contact with the necks. My theory is that dissimilar metal corrosion had occurred, which a) embrittled the brass in the necks, and b) "cold welded" the bullets in. They were quite difficult to pull. (These were not moly coated).
Jim

 

[Brians356]

I got a couple of boxes of factory ammo with a Steyr Mannlicher .22-.250 a few years ago. The ammo boxes and cases all looked just fine, but firing them split the necks on at least half of them, so I discarded all the brass. I unloaded the second box, and the bullets all had black discoloration on them where they were in contact with the necks. My theory is that dissimilar metal corrosion had occurred, which a) embrittled the brass in the necks, and b) "cold welded" the bullets in. They were quite difficult to pull. (These were not moly coated).
Jim

Embrittlement makes some sense I suppose. "Cold "welding" does not. I find it hard to credit that copper will "weld" to brass strongly enough to resist the expansive pressure inside the case. I wouldn't think any such adhesion could be much harder to overcome than a firm case mouth crimp.

Find a round allegedly "cold welded" and, using a mechanical (not inertial) puller, see if the bullet won't come out without splitting the neck, or leaving some jacket behind.

 

[jimbires]

years ago I had some ammo I loaded at the most, 6 months before I shot it . this brass was bought new and fired one time , in this rifle . on the second fire a couple pieces of brass would eject and the neck would still be in the chamber . I was not annealing brass at this time , and just figured it was brittle brass . so one day I start to pull the bullets and the neck came off of two more pieces of brass . if you look closely you can see the corrosion on the bullets , especially the bullet on the right . Jim

 

[Brians356]

years ago I had some ammo I loaded at the most, 6 months before I shot it . this brass was bought new and fired one time , in this rifle . on the second fire a couple pieces of brass would eject and the neck would still be in the chamber . I was not annealing brass at this time , and just figured it was brittle brass . so one day I start to pull the bullets and the neck came off of two more pieces of brass . if you look closely you can see the corrosion on the bullets , especially the bullet on the right . Jim

The brass certainly seems brittle to me. The presence of corrosion does not prove adhesion was strong enough to cause good brass to fail. It could be the brass was perfectly within specs (and not brittle) but how can we know for sure? Just the engineer here, being cautious.

Can you explain how so much corrosion appeared after only 6 months? Under what conditions was the ammo stored? How was the brass stored between first firing and later reloading?