Mosin-Nagant issue

[Herk]

I took my "new" Mosin out the other day to shoot it. I had had to clean out the cosmoline myself (used the solvent tank at work) and then I took it to the range a couple of days later. I shot one shot at 100yds (hit!) and then tried to work the bolt. I know that Mosin actions will never be called smooth but this one took a LOT of effort to even lift the bolt handle up. Since I couldn't pull the bolt back I had to kick it open. The case ejected and was badly split. The next shot was at 200 (another hit!) and same result: action needed kick-starting and this case was, if anything, more badly cracked/split than the first. After that I shot it no more.

The headstamp of the ammo (steel cased, kind of a coppery-colored finish to it) was a "46" and a "60" equidistant from each other. The 'packaging' was some thin paper, yellowed with age (or chemicals) and tied up with twine.

The bolt closed very easily and it chambered the ammo with no problems. It was only after the shots had been fired that I experienced trouble.

Is my rifle safe to shoot? Is the ammo to blame? Is there anything I'm not considering?

Thanks!

[ray1970]

Is my rifle safe to shoot?

I don't think I'd trust it. Sounds like some sort of chamber or headspace issue to me. Hopefully Bert will be along shortly with a more expert opinion.

[rondog]

Mosin's typically need to have the chamber "scrubbed" of cosmogoo with strong degreasers, or even immersion in boiling water. A lot of guys will use a piece of cleaning rod and a 20 gauge brass brush in a cordless drill, soaked in Hoppes or similar, to polish the hell out of the chambers. Same with the bolts, they get packed full of goo and need to be dismantled and totally cleaned, inside in all the nooks and crannies. I know you used a parts washer, but there's probably a LOT of goo that you missed and that washer will never get. Don't be afraid to use an old pot you can throw away, fill it with water and get it to boiling on a camp stove, turkey fryer, whatever, and then immerse the rifle parts into the boiling water to melt that snot out. Stick the whole action in it and swish it around, boil it out and then scrub the nooks and crannies with solvents and brass brushes.

The boiling water will get the parts hot enough to evaporate any residual water, so rusting isn't a problem. You'll oil it up afterwards anyway.

Cleaning up old guns packed in cosmoline makes you wonder just WHO thought it was a good idea in the first place. Mosins are great rifles, but there's a reason a lot of guys carry a piece of 2x4 to the range with them.

Oh, and there's certain types of Combloc milsurp ammo that have a lacquer coating on them, that stuff tends to grip the chambers and causes grief too. I'd avoid that stuff.

Don't know what to tell you about the split cases, I've had several myself and never worried about them. I've even found new ones that were split. I don't think quality-control was high on Combloc countries lists.

[ray1970]

Everything rondog said is true. But I don't think it would cause the cases to split if you left some gunk in the chamber.

I could be wrong.

Where the hell is Bert?

[zteknik]

Definitly sound's like a case of hardened coz in the chamber.like it was mentioned a real good scrubbing (and a pick) would be in order.
Dried cosmoline is like concrete.Takes a couple of times to get it out.
As far as the split cases sound's like you have some of the older Bulgarian stuff.Not all that uncommon to find split cases.Look over them good before loading to see if you can find any flaws in the neck.

B.P. could check it out for you and be able to tell if you have a headspace issue or not.

[BPTactical]

DO NOT FIRE THE WEAPON!

What you are describing is classic excessive headspace. The case is splitting because it is not supported correctly at the neck and the bolt is difficult to open because the case is hammering it back into the receiver and bulging.
Come see me.

[USAFGopherMike]

I'm a Mosin shooter and have never had a problem.. However, I'm always looking for another Mosin owner to shoot with. I cleaned mine 3 times with hot water and degreaser before I got it really clean.

[rondog]

DO NOT FIRE THE WEAPON!

What you are describing is classic excessive headspace. The case is splitting because it is not supported correctly at the neck and the bolt is difficult to open because the case is hammering it back into the receiver and bulging.
Come see me.

You heard the man...the expert has spoken! Heed his advice.

[Herk]

Thanks for the replies. I totally dismantled the bolt to clean it so I know that's good to go. I guess that the headspace must be the problem. I hold off shooting it until that gets fixed.

[USAFGopherMike]

I hope it turns out to be gunked up. If not, can it be fixed with a new bolt?

[cstone]

I will defer to Bert, but I believe there are different sized bolt heads available and some work can be done to most bolt heads to assist with headspace on a Mosin.

Such a simple design and very effective. If I had to manufacture 100 million effective battle rifles, I could only use 13 man hours per rifle, and my budget was 15 Rubles per rifle, I wouldn't think real long or hard about which design gets chosen.

[USAFGopherMike]

I will defer to Bert, but I believe there are different sized bolt heads available and some work can be done to most bolt heads to assist with headspace on a Mosin.

Such a simple design and very effective. If I had to manufacture 100 million effective battle rifles, I could only use 13 man hours per rifle, and my budget was 15 Rubles per rifle, I wouldn't think real long or hard about which design gets chosen.

You gotta admire the Russians for their reliability to cost ratio. I've put over 700 rounds through mine without a single failure.