Primer Blanking with RWS 357 Mag Ammo

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Hi All,

I just purchased a Model 27-3, and noticed that with RWS .357 Mag 158 gr. ammo, there is a small hole in the fired primers, with what looks like soot deposited in the firing pin mark. I've attached a picture of two primers with this problem. I fired maybe 25 rounds, and around 7 had this. I also fired around 25 rounds of Fiocchi 125 gr. .357 Mag, and none of them exhibited this. I believe this problem is known as blanking, but I haven't been able to find any mention of this occuring with factory ammo.

I also shot about 100 rounds of 38 special handloads, with WSP primers, not max loads, and found 1 with this mark on the primers.

Any ideas as to what could be causing this? Has anyone else observed this?

Thanks!

 

[Troystat]

Does not look like excessive pressure, maybe the firing pin is a touch long. I have not seen that before.

 

[Dragon88]

Those are pierced primers. Is your firing pin excessively worn, or has it been sharpened? The tip should be rounded and smooth.

 

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Here's a picture of the firing pin. It looks okay to me, but this is my first gun with a hammer mounted pin.

There's a tiny spot on the tip of the pin that looks slightly worn, I think the finish has worn off in this area.

 

[Dragon88]

Hmm, if it had just been the one load I'd chalk it up to ammo, but you said it also happened with a WSP handload. Do the primer strikes from this gun seem excessively deep, even on primers that do not pierce?

 

[john traveler]

Excessive firing pin protrusion.

This can also happen with cylindrical firing pins that have a "teat" on the tip left over from the machining or grinding.

In your case, the excessive pin protrusion is crushing the anvil and thinning the primer cup to cause the leak.

 

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Do the primer strikes from this gun seem excessively deep, even on primers that do not pierce?

They might be on the deep side, but it's hard to compare. I did notice that even the primers that did not pierce have a tiny, shiny spot in the center of the primer that looks like its been indented extra. Maybe this is the thinning of the primer cup.

So what's the cure?

 

[Dragon88]

Have your firing pin protrusion checked by a qualified gunsmith.