Firing pin?

[ssgross]

My first times to the range with my trapdoor showed a mix of primers that split open.
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Took the pin out, and looks like there is some deformation in the tip...looks like previous pitting. The second 2 cases that didn't split show the imprint of the deformation.
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sorry, it's a hard part to focus the camera on. I don't think my loads were too hot...details are in my range report here. I remember the first time out, the very first round split, the next 4 did not. Leaves me to believe the I should have inspected the pin closer when I disassembled and cleaned it up. Cleanup thread is here

I have another firing pin on the way from the quartermaster's store as a backup while I try to save this one by stoning it nice and round again.

Information

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[Daan Kemp]

Too soft primers?

[browningautorifle]

I kind of side with you on too much protrusion. There must be spec at hand somewhere here for firing pin protrusion...the ones that didn't pierce are right to the bottom and that ain't right. The firing pin in it could have been put in any time over the last 150 years and needs tiddled up. Just polish it round and see. I've worked with Federal primers for years and don't see that, they're soft.

[ssgross]

I've worked with Federal primers for years and don't see that, they're soft.

The issue is discussed in other forums. In many cases, with no spring on the pin the primer gets driven back flush against the bolt face, and the "larger" trapdoor firing pin hole acts like a cookie cutter and the middle part of the primer blows. I thankfully don't have that problem. Other instances there were burrs or deformation on the pin tip, other instances a combination of these two problems.
The primers don't show any flat area from working out rearward. 5 out of 20 means I think you are right Jim. Just polish up the tip nice and round and should be good to go.

[ssgross]

that was easy...just chucked the pin in the drill press and worked the tip round with cloth backed paper.
Attachment 121044
maybe someone who doesn't have this problem at all can measure the protrusion of their pin for comparison?

[Low & Slow]

Recently had my 1873 apart, and was disconcerted to find the firing pin had become a two-piece affair. Found an original replacement. Test firing was satisfactory. Full protrusion is just shy of .090" as best I can measure without further tear down. Hope that's of some use.