Jacket separation

[Matt Cheely]

Interesting thing happened at the range this week while Tiny Warrior and I were out practicing for the Ontario Provincials.

I'm watching her shoot her open gun and she shoots a popper. Bit more smoke than usual out of the comp and the next round doesn't load. I pull the gun apart and there's something stuck in the barrel. Get home and pop this out of the throat of the barrel.

Yes, that is a jacket from a Zero 125gr JHP. The lead hit the popper, ejected the brass, but left this completely expanded copper jacket pressed into the sides of the throat. Interesting problem that I have not heard of before...

[HSMITH]

You used to see things like that fairly often with half jacket bullets and light loads, have only ever seen it with a hollow point once and it was a Remington 125 in a 357 mag....

[superdude]

wow!! that seems nearly impossible, from a practical point of view. shouldn't the gas pressure push out any "obstruction"? assuming there is enough gas pressure in the first place.

i can't tell from the photo, but was the base of the jacket intact? i'm assuming it was and what we're seeing is just the copper cup that the lead core was molded into.

if i had to guess i would have thought that if it was a light load that the whole bullet would stick. it's just so hard to imagine that the lead core would continue moving forward is the copper jacket stopped. its hard to imagine the the bullet had enough inertia after moving such a small distance to allow the lead core to separate and continue onward (it being the heavier element) when the jacket can't get pushed through the bore.

but the world is full of amazing stuff!

[gm iprod]

Heard of it once or twice before as well.

Damned lucky that stuck in the throat not further up.

I am only guessing here. But, is the base intact or did it blow through the jacket? Becuase, looking at that jacket, I am suspecting you had a light load (no or low powder).

Anyone who thinks I am mistaken may very well be right.

Edited to add.

And I hate people who can type faster than me.

Edited September 20, 2008 by gm iprod

[Matt Cheely]

It's a copper tube. The lead & copper base of the bullet hit the popper.

The round had a full load of powder. The only difference between it and a normal round was a bit more smoke.

Edited September 20, 2008 by Matt Cheely

[JThompson]

Hmmph!

[superdude]

ah, that makes sense. can attribute it to a weak/thin/fragile base of the copper cup.

[superdude]

how far past the chamber did the "tube" go? its a little hard to make out the riflings from the photo.

[Matt Cheely]

how far past the chamber did the "tube" go? its a little hard to make out the riflings from the photo.

The base was right at the front edge of the chamber. A piece of unloaded brass would almost make it in the chamber all the way. The jacket had moved maybe .050" forward from where it would have set in the chamber in the loaded round.

[superdude]

gm iprod

Edited to add.

And I hate people who can type faster than me.

sorry about that

[Flexmoney]

Weird. I haven't seen one, and this is the only one that's happened to somebody I know.

Probably only happens when practicing for a big match.

What could lead to that? Base of the jacket thin? Throat dirty/contact? Over-sized bullet? Under-sized barrel ?

[el pres]

Did you chamber check these rounds ? Could that bullet have been slightly oversized and

still managed to chamber tightly ??

[gm iprod]

superdud

I can't blame you for my own failings, that's the fault of my father, just ask my mum, nearly everything is his fault.

Back on subject.

Would having a heavy crimp cause the projectile to deform enough to allow the core out?

Or are we just dealing with one that got away from the factory?

[superdude]

wow...... Tiny Warrior is very lucky. that could have been a catastrophic disaster if another round had been chambered and fired!

[Matt Cheely]

Chamber checked. Win brass, WSR, 8.0 3N37, 1.165 OAL. Same load that I used to run in my open gun, in fact I think it was left over ammo that I had from when I was shooting open. They all ran fine...

[el pres]

It had to be a thin base and once it broke through the presure just sealed the jacket

against the throat ??

[superdude]

gm iprod

you typed superDUD

have you been talking to my girlfriend???

back on subject:

okay! i'm giving up jacketed hollow points!!!! i'm going back to cast bullets!!

[JThompson]

It had to be a thin base and once it broke through the presure just sealed the jacket

against the throat ??

This seems the most likely..

Edited September 20, 2008 by JThompson

[SLM]

... in fact I think it was left over ammo that I had from when I was shooting open.

Well there's your problem Matt. Old ammo. It probably got stale sitting around. Happens to bread, must happen to copper too! We just didn't know that!

Seriously, glad nothing really stupid happened and she didn't get hurt.

[XRe]

I know of cases where that exact thing has happened. In every case, it was attributable to extremely high chamber pressure exceedingly the capabilities of a marginal bullet jacket. Basically, pressure and temp burn right through a thin jacket and punch the core downrange, leaving the jacket (which has a higher resistance from the barrel than it does the lead core) stuck in the throat. Just thank God you couldn't chamber anything behind it

[JThompson]

Taking Dave's comments to heart... what do the primers look like?

[bkeeler]

Never seen that before!

BK

[herky]

Matt, I had the same thing happen early this spring. Ninth shot on a 24 round COF, the jacket separates half way down the barrel while I see a hit on the target, tenth round shoots thru the jacket, bulges the barrel, and hits the target. Gun locks up because slide cannot move past the bulge. Gunsmith extracts the jacket after he managed to get the gun open.

No one had ever seen that before. FWIW bullets were Precesion Delta 200 jacketed 40's. Never would have known it happened if the slide hadn't stopped moving.

[Matt Cheely]

Taking Dave's comments to heart... what do the primers look like?

They look fine. I know of at least 3 other open shooters locally that use the same load. Even if you use WSP they look fine.

I'm betting that it's just a fluke, poor bullet construction. But we're usign Montana Gold bullets now anyways, these were just being shot up for practice.

Edit: Meant small pistol primers...

Edited September 21, 2008 by Matt Cheely

[JThompson]

Taking Dave's comments to heart... what do the primers look like?

They look fine. I know of at least 3 other open shooters locally that use the same load. Even if you use WSR they look fine.

I'm betting that it's just a fluke, poor bullet construction. But we're usign Montana Gold bullets now anyways, these were just being shot up for practice.

Be sure and let us know if you see it again or if you figure out what happened.