View Full Version : What causes a primer to do this?

April 19, 2009, 04:04 PM
These are 3 different brands of ammo fired in the same rifle. Somehow it is blowing the primer out the back of the case. There are no other signs of pressure except carbon around some cases, but I would think that is caused from the primer blowing out.

The weapon is a PPSH-41, manufactured by Wise Lite Arms. It is my little brothers, not mine, but he is in Iraq right now so I'm trying to figure out what the problem is for him. Thanks for any help.


April 19, 2009, 04:46 PM
substantial Overpressure!!!!

April 19, 2009, 04:49 PM
I hope you wear saftey glasses.

April 19, 2009, 05:02 PM
substantial Overpressure!!!!That would be my guess as well.


April 19, 2009, 05:50 PM
Not likely over pressure. If it was an over pressure problem, the round edge of the primer face would be flatened. More likely a too large hole in the bolt face that is allowing room for the primer surface that is unsupported by the hole to be extruded into the hole. Is this a new gun? Has this gun always shown this symptom on the primers?

April 19, 2009, 05:55 PM
Dangerous overpressure. If you are in North Texas, take it to the Wise Lite Arms plant in Boyd (northwest of Fort Worth, south of Decatur).

April 19, 2009, 06:05 PM
Thanks for yalls help. I really appreciate it.
They are not reloads. Two brands of factory ammo and one surplus. I didn't think it would be overpressure because like I said there are no other signs. I load my own ammo and have seen pressure signs like a smashed case head, split cases, and the primer being flattened out against the sides of the primer pocket. But there are none of these. Just a blown out primer.
He bought the rifle used at a store here in town. I was hoping there would be some other course of action besides taking it to the manufacturer.
Is there any way that the firing pin might be puncturing the primer? Thanks again.

April 19, 2009, 06:13 PM
Oversize firing pin hole

WildmyguessAlaska TM

April 19, 2009, 06:25 PM
Exactly. The firing pin hole needs to be have a bushing installed, or more likely, have the bolt replaced.

James K
April 20, 2009, 02:07 PM
I am not familiar with that semi-auto PPSh, so some of this is guesswork.

First, it is NOT overpressure. Is the firing pin of normal size and does it fit snugly in the bolt, or is it a tit on a firing pin rod that fits inside the bolt?

If the firing pin is the normal type, it looks like the firing pin hole is supposed to have a bushing and it somehow got lost or pushed back into the bolt. If the firing pin stud is part of a rod, the firing pin spring is too weak, possibly cut down or weakened to reduce trigger pull.

The recoil spring may also not be strong enough or the bolt mass too little as the primers also seem to be backing out.

IMHO, it sounds like a factory problem and a factory job to fix it.


Mike Irwin
April 21, 2009, 09:12 AM
I saw something like that years ago in a Smith revolver that had the firing pin bushing removed from the recoil shield.

I agree that there's no indication of overpressure.

This gun needs to go back to the manufacturer for repair immediately. That it hasn't actually popped any primers is something of a miracle.

April 22, 2009, 10:23 AM
Thanks yall. I'll update when I find something out. It will be a while though as my little brother will be in Baghdad until later this year.

B. Lahey
April 22, 2009, 10:37 AM
I had a garbage Allied Armament PPSh that would do that, among many other scary malfunctions. Send it back, maybe Wise-Lite will actually fix it (AA never was able to fix mine).

You haven't popped any primers completely out yet? That's a fun experience...

Hot gas breeze softly scorching your face. Burnt beard hair stinks.:barf:

April 23, 2009, 10:14 AM
On second thought, probably what Wild said. (He HAS to get it right occasionally!!:D)

April 28, 2009, 02:28 AM
I'd try chambering a round from the magazine and ejecting without firing. Look to see if the bullet is engraved by the rifling or indications that the neck of the cartridge has been compressed against the bullet.

Cheap test at least. If you see either of those conditions the chambering is causing overpressure.

April 28, 2009, 02:33 AM
Must be gun related

I reckon WildA is on the right path re firing pin problem :eek:

Check for barrel constriction as well :D

Wear body armour (full)