View Full Version : firing pin clearance, mosin

August 3, 2009, 07:37 PM
I jumped on the bandwagon and bought a mosin nagant 91/30. the issue I have is that the firing pin is .011 under the firing pin port. pin measures .091 checked with a mike and the port .102 checked with pins. I shot sellier & bellot ammo and the primer is extruding into the firing pin port around pin, not alot but I did measure it at .005. I installed a new wolff firing pin spring so its not a weak spring. the primers are not flattened from excessive pressure. I measured a friends 91/30 and dimensions were almost identical, within .001 on each and I also bought a surplus firing pin and bolt head, again near identical dimensions. has anyone else noticed this and is it how they are made? I checked the clearance on several different firearms I have and .002 seemed to be the norm. if either dimension is out of tolerance , where is the best place to get GOOD replacement parts. if this how the ruskies made them what is the best method to fix this. also the other rifle I mentioned also shows the same extrusion issues. thanks

James K
August 3, 2009, 08:24 PM
A good description, but what problem is it causing? That is not a huge amount of tolerance, and I am a bit surprised there is any primer backflow at all. S&B must be using soft primers. Anyway, if it isn't hanging anything up or leaving part of the primer inside the bolt, I wouldn't worry about it. If you reload, you might consider using harder primers, but with factory ammo you are pretty much stuck. You might also try some Russian ammo and see if that helps, but avoid the old military corrosive stuff if you can.


August 3, 2009, 08:49 PM
[QUOTE] but what problem is it causing?[QUOTE] I should have pointed out that that was one of my questions, sort of. at what point does this situation lead to a blown primer? or can it? based on what you've read I shouldn't be concerned? yes I do reload and I will be using the s&b brass and if harder primers will help I may try some cci34 primers.