Sporterized Mosin Nagant Questions

[Bored1]

Just got home from a trip to a local pawn shop and stumbled across a sporterized Mosin for a pretty reasonable price. I have actually been contempling trying to find one for the upcoming deer season since I already have a 91/30 and its no fun to drag that around after deer.

Anyways my questions are about headspace. I am no gunsmith so excuse my ignorance in this matter. I have heard that excessive headspace is dangerous and am wondering if there is an easy way to check this while in a pawnshop without disassembling anything and in a way that wont get me kicked out of the shop!!! None of the #'s on the gun in question matter, and it does already have the bolt turned down if that makes any difference. Any ideas or suggestins are greatly appreciated!!!

[StratsMan]

First, I'm not a gunsmith and I don't play one on TV....

The Mosin Nagant, if in the original chambering, is 7.62x54R... that capital 'R' stands for "Rimmed"... That cartridge doesn't headspace on the shoulder of the case like a 30-06 Springfield or 223 Remington. It headspaces on the rim, so the distance you need to measure is the distance from the bolt face to the breech surface under the rim of the cartridge. So the headspace gauge is very short compared to an '06 headspace gauge.

Still, you can't really measure it accurately without a gauge...

[texassako]

I have the coin style headspace gauges from Okie Headspace Gauges for the 7.62x54R and .303/30-40. It is cheap $25 insurance to get the field gauge IMHO, and every time I think of selling them I end up buying another rifle. No disassembly required for use since they have a firing pin hole and extractor cutout.

[I'll Make Mine]

I made a set of headspace gages on my lathe after I bought my 91/30. I turned down a piece of threaded scrap to rim diameter (.570"), turned a spigot a rough half inch long sized to fit nicely into the tapered chamber (as I recall, I used .470" diameter -- needs to be a bit smaller than the .486" nominal head diameter just ahead of the rim), cut the piece off the stock, repeated until I had three blanks. I then chucked the blanks with the large end visible and faced off the large end, pulling them out to measure the rim thickness frequently, until I got one at .066" ("go"), one at .071" ("no-go") and one at .074 ("field"). I then ground notches in each rim with my Dremel, deep and wide enough to clear the extractor. Finally, I stamped the rim thickness into the forward end of each gage piece along with "G", "N", and "F" (for "go", "no-go", and "field").

To use these, place the gage on the bolt face with the notch over the extractor, and close the bolt. The bolt should close completely on the "go" gage (if it doesn't, you'll have trouble chambering a factory round), and for a freshly refurbished rifle should not close all the way on the "no-go". If it does, it's still safe to fire as long as it won't close on the "field" gage ("no-go" is a factory and refurb standard, "field" is the actual maximum allowable headspace). I was very happy to note that my 1943 Izhevsk 91/30 (post-war arsenal refurbished) closed on "go" and stopped about 30º of bolt rotation short on "no-go" -- just like a new rifle should.

Most of the commercial headspace gages I've seen for 7.62x54r are the coin type, probably stamped or water jet cut from precision ground sheet stock, but this method is a great deal easier if all you have is a little 7x12 lathe, dial caliper, and some scrap...

[Gtek]

Cheap and dirty, Take A/C tape and cut disc to fit on back of fired cases. Stack to create shim stock. Place on bolt face under extractor and index finger in chamber. If it eats .010" or so on the tail of one I would start leaning back. But how cheap is it? bolts are not that much. If it is in the 1 bill range, why not go buy a whole one and carve it the way you want. Gtek

[I'll Make Mine]

For whatever it's worth, from what I've been reading, most Mosin Nagants coming from arsenal storage with mixed, electric penciled, or restamped numbers are just fine for headspace. They get the numbers mixed up because the arsenals swapped parts to get things within refurbish tolerance -- which means they actually were tested and fitted. Mine, $120 at a local shop, straight out of the importers plastic bag and the old cosmoline, closed on a .066 "go" and didn't close on a .071 "no-go"; I wasted the effort making a "field" gage (well, it was good practice doing zero-tolerance work on my lathe).

A .010" shim behind a fired case is still under the "field" gage of .077 (factory case rims are .064" nominal), so should be fine to fire (this won't change noticeably over time, BTW -- it's a question of tolerance stacking in the parts assembled by the arsenal at the last refurb). If the shim that stops it closing on a fired case is .013" or more, you have a headspace problem. Solving it doesn't require replacing the bolt; at most, the bolt head (the piece that carries the extractor and has the locking lugs on it), which sells for around $25 these days (though there's no simple way to be sure a mail-order bolt head will correct a headspace problem).

[helice]

Send us some pictures of it. Its always fun to see how someone "sporterized" a mil-gun.

[Bored1]

I think Im just going to pick up a cheap m44 and sporterize it in the future. The gun is god knows how old and of questionable origins since its at a sketchy pawn shop. Went in again and asked th egun guy if he happened to have a headspace gauge and his answer was "Its a rimmed catridge, no need to check headspace. Before these imports in the last few years Ive never seen those with matching #'s. Why do you care? Thata gun was probably imported back in the 60's and been used every deer season since then. You want it or you don't. Ive never had any problems with any of the old mosins so dont worry about it"

[Fishman]

Probably no need to sporterize the m44 when you get it. It's pretty handy just the way it is. I like mine.

[siamese4570]

+1 on what Fishman said. I have an M44 that I put an S&K mount and cheap BSA 2X pistol scope on. shoots great (with reloads) and I can put it back to original if I want to. The mount replaces the rear sight and is a no-gunsmith mount. The mount is a little pricey but it has never moved. Read about cheap internet models that do. If I were picking out an M44 to hunt with, in addition to everything mentioned above, you also want to see how easy the safety is to engage. My m44 safety is a challenge while my 91/30 hex is really easy. Just my $0.02 worth.

Siamese4570

[Josh Smith]

Hello,

It's probably OK as was mentioned. It takes about a case of compressed Bullseye to stretch the action. (Actual test by a gunsmithing school.)

As for 'scope mounts, I much prefer the stuff by Brass Stacker. You retain the option of going to the iron sights for backup... which I naturally like.

Here's a quick review, and I must apologize for running out of ammo and not hitting the target. Still, I got a group representative of what this mount and 'scope combo can do:

http://i4.ytimg.com/vi/gqQwHrbZ2rA/mqdefault.jpg
Smith-Sights Solution: Brass Stacker's Mosin Scout Mount Installation and Test (http://www.youtube.com/watch?v=gqQwHrbZ2rA)

This exits you to YouTube; I do not see a way to post vids here. Clicking with the middle mouse button should open a new tab or window.

I hope this is useful!

Regards,

Josh