Mosin-Nagant Extracting Issues

[Scrungus]

I just bought a 1940 Finnish M91 and it's having some issues when it comes to extracting the spent casings. If I throw 5 bullets in and just rack through them they all eject, but when I shoot them it's hit or miss whether casings get extracted. I will pull the bolt all the way back and the casing is still there in the breech, so I run the cleaning rod through it and the casing comes out with little resistance. The extractor looks a little bent, but I don't have another to compare it to so I don't know for sure. If anyone has any suggestions I'm all ears. Thanks!

 

[Wannashootit]

If I throw 5 bullets in and just rack through them they all eject, but when I shoot them it's hit or miss whether casings get extracted.

If this is happening only on fired cases as the gun heats up, it's probably "sticky bolt syndrome".

What's that status of the rifle- has it ever been thoroughly cleaned?
I've worked on hundreds of MNs, can't tell you how many that have come in are still dripping fucking cosmolene from the action.

If there's cosmolene still there, when the rifle heats up it liquefies and causes the cases to stick.

Other possibilities:
Extractor looks fine from what I see. However, same potential problem due to cosmo/crap- make sure the extractor flexes freely, push on it with a punch. Sometimes it will literally be stuck to the milled slot in the bolthead.

Did you check headspace?

 

[Scrungus]

I pulled the barrel out of the stock and got the visible cosmolene off and then I ran a boresnake through it about 20 times before I shot it, but I know I didn't clean the chamber or under the extractor very well. And no, I didn't check the headspace. Looks like I have some troubleshooting to do. What's an effective way to get the cosmolene out of the action?

 

[MK20]

A new extractor is cheap if you want to check to see if that is the problem.

 

[Ledzep]

20 gauge brush, mineral spirits, drill.

Scrub the chamber harder than you think you should.

 

[roostercogburn98]

If you don’t care about the finish, kerosene will take it off.

 

[Wannashootit]

Looks like I have some troubleshooting to do. What's an effective way to get the cosmolene out of the action?

What Ledzep said... the 20 ga chamber brush is a good fit. Me, I use brake cleaner 'cause I don't like fucking around with it for hours.
I'd pull the action from the stock, hold it muzzle down and spray heavily into the receiver, crud accumulates at the breech around the extractor groove and lug abutments. If you go that route- you must immediately lightly oil all the surfaces after and run a lightly oiled patch down the bore so nothing flash rusts.

I ran a boresnake through it about 20 times before I shot it,

I never get paid for it...but I can't stand the shit condition of the bore that many of the MNs come in with so I clean them for the customers.
The Finn rifles are always in much better shape if for no other reason than they didn't use corrosive primed ammo. Still, you should give it a real cleaning. I use Wipe-Out and multiple (many multiple) overnight soaks until the patches stop coming out blue. They didn't have copper solvents back in those days. Clean it like you would your expensive rifles and you might be surprised what it'll print- the Finns made some seriously good barrels, the M39's in particular are crazy accurate with match ammo.

 

[Scrungus]

I tried pretty much everything suggested: I used a 20 gauge brush with mineral spirits. Headspace is good. I went to shoot it and the same shit happened. I replaced the extractor today and now there are no issues. Thanks for all the suggestions!

 

[Digetydog]

If this is happening only on fired cases as the gun heats up, it's probably "sticky bolt syndrome".

What's that status of the rifle- has it ever been thoroughly cleaned?
I've worked on hundreds of MNs, can't tell you how many that have come in are still dripping fucking cosmolene from the action.

If there's cosmolene still there, when the rifle heats up it liquefies and causes the cases to stick.

Other possibilities:
Extractor looks fine from what I see. However, same potential problem due to cosmo/crap- make sure the extractor flexes freely, push on it with a punch. Sometimes it will literally be stuck to the milled slot in the bolthead.

Did you check headspace?

It took me days to get the cosmoline out of my Finnish Mosin only to have it stolen before I got to shoot it.

I would let the wood heat up in the Texas heat and it would seep out on to the the cardboard I had it on. I cannot remember how many times I did that before it came out dry.

 

[Haney]

I tried pretty much everything suggested: I used a 20 gauge brush with mineral spirits. Headspace is good. I went to shoot it and the same shit happened. I replaced the extractor today and now there are no issues. Thanks for all the suggestions!

Good to see a happy ending with an easy fix .

 

[Wannashootit]

I replaced the extractor today and now there are no issues.

Glad to hear it. I still don't see anything obviously defective with the extractor in your original pics. They are "bent" (as in, not flat) as you said to angle in so they seat flush against the groove milled in the bolthead. Top lip is angled a bit downwards so that when pressed against the rim when bringing the bolt into battery they're pushed outwards then snap back over the top of the rim. Typically very reliable, perhaps the underside of the lip was worn to where it could get pushed back out in primary extraction. Just curious- were you able to determine exactly what the problem was with the original when you put them side by side?