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06-02-2017, 05:24 PM
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7.63 Mauser Pistol Pierced Primers Cause
I fired some of the PPU 7.63mm x 25mm ammo in my C96 Mauser today. Functioning and accuracy was good but I had a few pierced primers. I bought the complete set of Wolff springs kit and installed the hammer spring and recoil spring before shooting it. I did not change out the firing pin spring and am unsure what the tip of the FP looks like. Will replacing the FP spring prevent this ? There are odd looking strikes on the primers that weren't pierced. What do you guys think ?
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06-02-2017, 09:14 PM
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Replacing the FP Spring could help - but since we do not know what is currently in there we do not know IF IT is the problem or not. Since you already have it, it wouldn't hurt to try.
I've fired some PPU 30-06 ammo with no issues, and everything I know about PPU claims it's pretty descent stuff. That said, you might want to try another brand and see what happens with that.
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06-02-2017, 10:03 PM
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It looks to me like the firing pin is going too far in on the anvil, causing a thin spot in the primer cup, and the pressure of firing is causing the thin spot to blow out sometimes. If you can regulate the firing pin to not go out as far, that might fix the problem.
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06-03-2017, 06:43 AM
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How long have you owned this gun? My first suspicion is someone has replaced the firing pin sometime during the gun's life, and that is the source of the problem.
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06-03-2017, 08:22 AM
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Your firing pin should be threaded. some replacement firing pins on the C96 are smooth. For some reason the threading keeps the spring from bunching up, holding the pin forward (sticking out of bolt) and causing slam fires.
How Mauser knew they had to do this to the C96 firing pin is beyond me.
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06-03-2017, 08:55 AM
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I would doubt the primers in the PPU ammo is the cause. I have used quite a bit of PPU in other calibers with no issues.
Never owned a C96 Mauser, so I cant comment on the firing pin, but will say that any semi-auto that is piercing primers is in danger of damage to the bolt face. I would not fire it again without fixing the issue.
Larry
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06-03-2017, 09:04 AM
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I would guess that the primers are soft or they are loaded a little too hot. The dimple in the middle of the indention appears to be the anvil of a bearden primer.
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06-03-2017, 09:34 AM
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I'm with the Chief, replace the firing pin return spring. There is no "FP Stop" as we tend to think of one in a C96. Protrusion is controlled by the relative strength of the return spring vs. the hammer spring. You just replaced the hammer spring, so you should replace the FP spring also.
(I pulled the FP on one of my C96's and removed the spring. When reassembled without a spring the FP will protrude a good 1/4 inch into the chamber and wont retract as designed. (slam-fire time??))
A weak or partially collapsed spring plus soft primers could cause all sorts of problems.
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06-03-2017, 12:30 PM
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Put the old hammer spring back in the gun and try it.
I suspect that since it's been changed out to a new Wolff spring, the hammer fall is now heavy enough to punch the FP deeply into the primers to have a few of them pierce. Even the ones that didn't pierce look very deeply struck. No need for that deep of an imprint to simply fire the primer.
Unless the original was very weak and either not firing the pistol or not giving sufficient resistance to the recoiling bolt to avoid frame battering, I'd leave it alone
Could be the primer cups are softer than normal, could be the firing pin spring is a bit weaker than a new one too,,but with nothing else in the gun changed (other than recoil spring and that isn't involved), I'd suspect a heavier than needed hammer fall(at least with that ammo).
Pull the firing pin back out again and check the tip for any damage, chips, ect.
Make sure the tip hasn't been filed or turned down a little to a smaller diameter during an earlier repair of a bent or damaged tip. Sometimes done after straightening a FP tip to true it up a little. But too much and it becomes an ice-pick of the firing pin and will pierce primers more easily.
I'd leave the new recoil spring you put in already,,that'll help protect from bolt stop battering,.
While it's out, may as well put the new firing pin spring in on the front of the pin. It's real job is keep the FP in the rebound position but it does offer some resistance to the hammer fall upon firing so a proper weight one will help somewhat to avoid the problem.
Last edited by 2152hq; 06-03-2017 at 12:34 PM.
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06-03-2017, 09:04 PM
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Thanks to everyone for their suggestions. I'll pull the firing pin, examine the tip and replace the spring first and fire a few rounds to see if that fixed it. If not I'll put the original hammer spring back in. That's a little more involved of a job but I know how since I have detail stripped and cleaned the gun before when I changed out the hammer spring. It sure does look like it's smacking the you know what out of the primers.
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