Mosin firing pin question

[ldlfh7]

Sorry if this has been beat to death but I wanted to ask a direct question instead of go through endless internet forums. I have an m39 which has no issues. My brother recently picked one up because he liked mine a lot. Issue with his is random misfires which I believe are being caused by light primer strikes. I checked the firing pin protrusion with the tool which came with mine and his firing pin does not reach to the top of the 1st gap for measurement. Needless to say the second measurement is also quite short.
I began adjusting the firing pin to meet the minimum protrusion length and though I had it all set. Once the bolt was back together, the rear end of the firing pin was no longer flush with the rear circular part on the bolt. The rear of the firing pin was noticeably recessed into the bolt. Mine is flush and lines up with the two hash marks on the back of the bolt.
Is it necessary for the rear of the firing pin to be flush with the rear of the bolt? If so, is this firing pin needing replacement?

Thanks for any help.

 

[easy]

How does the tip of the firing pin look? Does it look like yours, or does it look like it's been filed or reworked?

Take them both out of the bolts and compare them. Look at the springs as well.

 

[illinoisburt]

Is it necessary for the rear of the firing pin to be flush with the rear of the bolt? If so, is this firing pin needing replacement?

Nope, and nope.

The design of the firing pin in basically a long screw. The method you followed is correct - screw in the firing pin until it is between the min and max protrusion as measured with the multi tool. That is the precise reason the tool was issued with the rifle. There is a good deal of thread in the bolt housing for the firing pin. Being below flush doesn't matter. It could be 1/4 inch below flush and still be secured. I would not be concerned with your description.

As noted I would check that the tip of the firing pin is smooth and rounded to avoid primer piercing.

 

[herrwalther]

Is it necessary for the rear of the firing pin to be flush with the rear of the bolt? If so, is this firing pin needing replacement?

Nope. The tip of my firing pin on my 91/30 was about 1/8" below the bolt face. And the tick marks on the back were not aligned either. Still fired fine. Go off the multi tool gauge.

 

[boom boom]

Do yourself a favor and buy one of the original (not copies) Russian cleaning gear kits. They have a multi-tool that checks firing pin protrusion-here is an image of one in use which the notches check if it is too long or too short. As long as it is between the 75 and 95 you're ok.
http://www.russian-mosin-nagant.com/cleaning/Clean_032.jpg