Weird ammo problem

[sammy]

I was shooting my new AK yesterday (review coming later today) and fellow Calgunner showed up and put a few rounds through the rifle. We were shooting Wolf 7.62X39 HP and they all worked great except for one round. He fired the rifle and the round sounded fine and ejected fine but a huge amount of smoke came out of the reciever. It looked like a smoke bomb. The barrel was checked for a squib and was fine so we chambered another round and got 2 light strikes in a row. I feild stripped the rifle and found the firing pin was not going all the way foward. I worked the firing pin back and forth and something came loose out of the bolt and it was fine. Very weird. Anyone have anything lke that happen?

[hawaii five-0]

Blown primer.

[CHS]

Blown primer.

Yeah, +1 to this.

I've even had this happen on my AR's (not even wolf ammo!). You get lots of gas out the rear, bullet goes downrange as normal, but the primer and anvil (if boxer) usually end up somewhere in your action messing things up.

On my AR, the primer cup actually ended up UNDER the trigger, and acted as a safety. I found the anvil but it took me a bit of fiddling around to figure out where the hell the primer cup itself was and get it out of there.

It's a pretty rare thing, but it happens.

In all my years of shooting I've only ever had 1 case-head separation, and 1 blown primer.

[Beelzy]

The round that made the smoke-bomb was the loose fitting primer culprit.

Yet another reason why I shy away from that stuff.

[jandmtv]

I have had that heppen with wolf ammo a few times in my father in laws AK.

[JeffM]

Loose primer. Live and learn... and practice your transition!

[ar15barrels]

Live and learn... and practice your transition!

If you are shooting an AK, do you have to transistion to a Tokarev or a Makarov?

[Sunwolf]

Actually

If you are shooting an AK, do you have to transistion to a Tokarev or a Makarov?

After one of those rounds it is best to transition to a Smirnoff.

[Moonclip]

Is a blown primer pretty much the same as a pierced primer? And a primer backing out is one step away from a blown primer?

[ar15barrels]

Is a blown primer pretty much the same as a pierced primer? And a primer backing out is one step away from a blown primer?

No.
A blown primer leaves the case.
A primer backing out is a sign of excessive headspace, not of excessive pressure.

[Moonclip]

When I shoot some hotter milsurp 7x57 Mauser in my Brazilian 1908 I get a lot of backed up primers. When I use milder Federal I only got one backed out in 20 rounds. So do I have a headspace problem or what? And is'nt correcting headspace expensive on a milsurp bolt gun?

[ar15barrels]

When I shoot some hotter milsurp 7x57 Mauser in my Brazilian 1908 I get a lot of backed up primers. When I use milder Federal I only got one backed out in 20 rounds. So do I have a headspace problem or what? And is'nt correcting headspace expensive on a milsurp bolt gun?

What you are seeing is long headspace.
The case sets forward in the chamber by the firing pin hit, then expands against the chamber walls and adheres due to chamber pressure.
The case is strong enough to NOT get pushed back against the boltface.
The pressue backs the primers out.

Softer federal brass will not hold the pressure and it stretches rearward.
That's why you don't see the primers protruding on the federal cases.

Get yourself a way to measure case shoulder-base length length and I bet you see distinct differences in the lengths of the cases that show a high primer and the ones that don't.
The difference in those lengths should be right close to the amount that the primers are protruding from the cases too.

Headspace can be corrected by swapping bolts out until you find one that tightens it up, or by setting the barrel back.
Headspace can also be corrected on the loading bench by simply adjusting your ammo to have longer shoulders.
It's much easier to make custom ammo than bring an old gun back within specs.