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Ruptured primers


justforfun

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Had a new experience today while picking up brass after some practice. I found 4 cases with ruptured primers which is a first for me. I had already picked up many others and have not gone back through them yet to see if there are any more. Here’s what I trying to figure out, is it a load problem or a gun problem?

My load:

180 Bear Creek RNFP

Mixed brass

4.6 gr Solo 1000

OAL 1.11

Fed SPP

My Gun: G35 with Lone Wolf barrel, I’ve been shooting this combo for almost 5 years.

I have shot several thousand of this combination with one exception, I switched from Fed small pistol magnum match primers to Fed small pistol about 1000-1200 rnds back. Chrono results changed very little if any with the switch and I didn’t notice any obvious pressure signs . This load has given consistent 170-172 PF for quite a while. When I got home I looked at my striker and it has some rough area/possible erosion on the end. The primers look a little flat and definitely have ruptured in the indent which makes me think I had high pressure. Could this be caused by the striker being rough/chipped or was the striker damaged by the gas from the ruptured primers? I’m kind of puzzled on this one and hoping someone here can help me find the cause of this.

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Had a new experience today while picking up brass after some practice. I found 4 cases with ruptured primers which is a first for me. I had already picked up many others and have not gone back through them yet to see if there are any more. Here’s what I trying to figure out, is it a load problem or a gun problem?

My load:

180 Bear Creek RNFP

Mixed brass

4.6 gr Solo 1000

OAL 1.11

Fed SPP

My Gun: G35 with Lone Wolf barrel, I’ve been shooting this combo for almost 5 years.

I have shot several thousand of this combination with one exception, I switched from Fed small pistol magnum match primers to Fed small pistol about 1000-1200 rnds back. Chrono results changed very little if any with the switch and I didn’t notice any obvious pressure signs . This load has given consistent 170-172 PF for quite a while. When I got home I looked at my striker and it has some rough area/possible erosion on the end. The primers look a little flat and definitely have ruptured in the indent which makes me think I had high pressure. Could this be caused by the striker being rough/chipped yes or was the striker damaged by the gas from the ruptured primers? maybe I’m kind of puzzled on this one and hoping someone here can help me find the cause of this.

a damaged firing pin (striker) surface is a well known cause of pierced primers. the way to tell if that is your problem is to re-face or replace it and see if the problem goes away.

whether the ruptured primers caused the damage to the striker i can't say. maybe. but i think the first thing to do would be to fix the current striker and see what happens.

the fact that the primers look a little flat might indicate that the pressure is high, and maybe the standard primers are showing it more than the magnum primers. but you can test that by trying more magnum primers along side the standard ones.

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I've had this happen a lot with Fed. primers mostly with 9mm Major Glock open guns. I think it's a combination of soft primers and a sharp striker, some are a little more pointed than others. Then once you have punctured a few the gas flame cuts the striker and makes it even sharper until finally it deteriorates it to the point where it's junk. I completely eliminated the problem by going to Winchester primers. Your O.A.L. does seem short I load to 1.135 for my G35

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Yes, the OAL is on the short side. With the throat on this barrel being on the short side I loaded shorter to keep loads passing the chamber check. I still have a few that won't chamber even at that length due to bullet run-out, but I'll probably extend it out some to see if that helps. Like I said, I have run many of these loads before with no issue, maybe I was just not seeing it with the magnum primers and am just know seeing it with the standard one. Thanks for the replies.

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Get rid of the federal small pistol primers. Federals are great in lower pressure loads, or in guns that really require a soft primer for reliable ignition. Some (including me) use small rifle primers for major 40 loads. Many major loads for .40 end up being a bit over SAMMI spec for pressure, thus flattening or piercing primers. Another option is to use a slower powder.

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Ran a little over 50 rds through the gun today after swapping out the striker and had no ruptured primers. I'm going to keep running it for a while and see how it does, I've go about 600 more of the same load to shoot up. I'm going to extend the OAL out some for future loads and see if that helps also. I think this may have been a combination of things and just started noticing it with the softer standard Federal primers. Thanks for the help.

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