Cold Weld- Theory or Fact?

[SFree]

Have a buddy who shot some 10 yr old factory ammo through a bolt gun and they all had flattened primers. Is "cold welding" or the boolits gettin sticky/stuck over time a possibility?
Told him to bump with a seating die to see if it makes a diff. Any thoughts?

 

[Deadshot2]

Re: Cold Weld- Theory or Fact?

I've had flattened primers with "New" factory ammo. Also, some primers are more prone to flattening than others.

I've found that Winchester primers tend to flatten even with weak loads. All a matter of metal composition.

 

[Fuzzball]

Re: Cold Weld- Theory or Fact?

Bullets "cold welding" to necks happens but it's not a real weld, more like getting sticky and it's hardly enough to raise pressures very much. Much more likely your friends chamber is a tad on the long side or the ammo shoulders were a tad short - or both. A sloppy chamber fit is the major cause of really flat primers.

 

[MitchAlsup]

Re: Cold Weld- Theory or Fact?

Most of the time, the powder is degrading slowly over time as oxygen "gets to" the retardents. This increases the burn rate and does nothing positive wrt pressure signs.

Paraphrased from the Norma Reloading manual 2004 pp 98.

 

[DocB]

Re: Cold Weld- Theory or Fact?

SFree,

Something does occur. You can feel the "snap", whether from case age hardening or cold welding, if you set bullets back 0.005 to 0.010" on handloads. I've tested with new and once-fired cases aged from one to three years.

HTH,
DocB

 

[bfoosh006]

Re: Cold Weld- Theory or Fact?

For me Cold Welding is fact. Years ago I was loading some .44Mag , made a "dummy" cartridge. After getting all the dies set up... ( and being a cheapskate ) I decided to pull the 300gr XTP ( brand new Nickel plated Winc. case ) I pounded that inertia hammer over and over.... so many times and so hard, that the lead core started extruding out of the copper jacket. I never did get the two virgin componants apart. It now sits on the shelf , as a reminder, that I don't know everything.

 

[Unknown]

Re: Cold Weld- Theory or Fact?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bfoosh</div><div class="ubbcode-body">For me Cold Welding is fact. Years ago I was loading some .44Mag , made a "dummy" cartridge. After getting all the dies set up... ( and being a cheapskate ) I decided to pull the 300gr XTP ( brand new Nickel plated Winc. case ) I pounded that inertia hammer over and over.... so many times and so hard, that the lead core started extruding out of the copper jacket. I never did get the two virgin componants apart. It now sits on the shelf , as a reminder, that I don't know everything.
</div></div>

Men who know they don't know everything, know more than men who know they know everything.