bush firing pin for me ?

1

1919Spooky

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For one reason or another I can't seem to find a smith who is willing to bush the firing pin on my mosin nagant. I pierce primers at a low pressure~40,000 psi (measured on my PTII machine). Will anyone here be willing to perform this job for me ? Thank you for your time
 
What do you think would be a reasonable charge for this work? Who would stick his neck out for such a job?
 
I'd pay them what they want and what is reasonable to me is less then the cost of machining a new firing pin, which would be allot. , probably 100-200 i guess , is that not reasonable ?

who would stick his neck out ? someone looking to help me with my problem I suppose. I pierce primers at a low pressure , i want it to stop , if i can find no one to bush my firing pin i imagine i will have to thinking about tig welding and re-drilling. But i hope someone here with machining expernice would take this job for me.but, Im not sure I understand your question.
 
Gra-tan they go out in a few days. They said they turn the bolts around quick. Did mine and back in a week.

Very pleased.

John
 
Have you tried a different brand of primer? I would try a different one with a heavy cup like the CCI BR first.
 
i did talk to greg and he told me russian steel isnt the best quality and that if things go wrong would cost him more money , so he said no. Several smith's had said no for different reasons , i dont work on military actions being the most common. I have tried several different firing pins, springs, and primers. I checked the headspace, and I believe i need this type of modification in order to fix this problem.

no one here with machining expernice is willing to take this job for me ? im not experniced but , what could go wrong ? if a tap is broken off i will pay to get it EDM'd out of there...
 
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the extremely low pressure is the biggest part of your problem. does it pierce primers with surplus or quality ammo? simple facts are, a good gunsmith is going to charge more than the value of the rifle for what you want done. in oyur shoes, i would first try ammunition of proper pressure, next i would swap out the firing pin and bolt head. if none of them cure the problem, i would replace the rifle as it would be cheaper than the labor to alter it.

as an after thought, have you set the firing pin protrusion??
 
yes i have played with the protrusion and i have set it at an ideal depth. I do not believe that is the problem. I think the problem is the O.D. of the pin is smaller then the hole in the boltface , i have tried several pins , pins with smaller O.D's would pierce/crater sooner then the pins that were slightly larger. So i think bushing the firing pin would solve the problem. I believe the solution to this would be reducing the clearence between pin and the hole , i thought about tig welding the hole and re-drilling , but i perfer to bush the pin if possible.
 
do not weld on the bolt face!!!!!!!!!!!!! seriously, pierced primers is usually a result of underpressure ammunition.
 
That is the first time I have heard of underpressure causing primers to pierce.
I have only seen it with the 204 and over pressure was the cause.
Could you please explain how low pressure causes primers to perforate
 
how much protrusion does the firing pin have , what is the firing pin OD, is the firing pin staying in the forward position after firing an not rebounding fast enough ,like weak spring or hanging up in the forward position allowing it to pierce as the pressure pushes back on the primer. Firing pin hole just doesn't sound like your problem . To me a larger firing pin hole would allow the pin to change the primer strike position an might vary primer flash but not priece. Now maybe this model does allow the firing pin to lay forward ? an protrusion would be very important .
 
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You might also check the shape of the firing pin tip. It should be round, but a slightly larger radius than the diameter of the tip.
Sharp or square can lead to similiar issues. Have seen many shapes on military guns.
 
I have never worked with one of these rifles, but would it be possible to remove, and drill out front of firing pin. Replace with a piece of close fitting music wire, or drill rod. As already pointed out, don't dry welding.
 
Mike A said:
That is the first time I have heard of underpressure causing primers to pierce.
I have only seen it with the 204 and over pressure was the cause.
Could you please explain how low pressure causes primers to perforate
Click to expand...

Mike, I had the same question. I've pierced a few primers in my time, and they've always been with loads that were either too hot or what I think are primers that were too hard. I've had primers that were so flat and cratered that they were positively ugly. I've also gotten cratered primers with warm loads that were due to oversize firing pin holes.

It seems to me that if the pressure's low, there's just going to be a dent in the primer cup from the firing pin while the rest of the primer looks unfired from the outside. I've personally experienced this when I accidentally loaded H4831 instead of H4895 (thankfully not the other way around).
 
the pin protursion is .035 , the pin O.D. is .090

airdrop wrote: " the firing pin staying in the forward position after firing an not rebounding fast enough ,like weak spring or hanging up in the forward position allowing it to pierce as the pressure pushes back on the primer...change the primer strike position an might vary primer flash but not priece"

I dont think so, but maybe ? Its funny , a buddy/gunsmith friend of mine shares same problem with his mosin , he is the one who suggested tig welding, If its hanging up , then its happening to both of us. You dont think the excess clearence between the pin and hole is the cause of the problem ? i think it must be , greg's website says " The correct course of action is to reduce the firing pin hole diameter." , that is what im asking someone here to do to my bolt.

I have tried 3 different firing pins , if you include my buddy who has the same problem , well thats 4 bad pins , i dont think that can be the cause( but what do i know)
 
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I haven't examined any of my nagant bolt heads but think it should be easy to do. If I had a spare head I would do it for you.
 
you mean you need two bolt heads ? i can provide you with that
 
Not that it should make any difference, but is that a Berdan, or Boxer primer in that cartridge. On certain rifles if the primer blow's, the gas force will try to recock the striker. What does the main spring look like? Does it look bound, or shortened? The fact that two rifle"s are doing this with three different pin's makes me think the problem is elsewhere. That rifle is a military arm. No matter what country make's them, they are anything but fussy to tight tolerance. Most bolt gun's have a .056 pin protrusion, and a have never heard of a rebounding firing pin on a bolt gun. It would be interesting to put a correct head space guage in this arm. The original bolt for that rifle could be some where between Moscow, and Berlin. Could you take a photo of the bolt completely apart? That may give a look at what is wrong.
 
firing pin protrusion is way too short, you need around .060". if in doubt use the little combo tool that comes with almost every mosin to set the firin pin, its a simple go/no-go tool and you really cant go worng using it for that rifle. too sum this up, too little pin protrusion coupled with an underpressure situation is whats almost certainly causing you and your "gunsmith" to suffer pierced primers with those rifles. for those that dont comprehend the low pressure problem, a cartidge loaded to a too low of pressure can act just like an extremely overpressured one. with there being insufficient pressure for the cartridge to expand and grab the chamber. couple that with too little firing pin protrusion and now you have a cartridge case hammered into the bolt face and the primer flowing back into the firing pin hole causing pierced primers.
 
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