Mosin impossibly sticky on empty open and close

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paladinj

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Hello everyone!

I know there are many Mosin sticky bolt threads but I have followed all advice I could find on the internet and forums and am still left with a sticky bolt.

I have an all matching stamped serial number '38 Red Letter Tula. Beautiful condition and excellent barrel with a very nice trigger, or at least it used to be. Depot 25 gave it some shims and perhaps a raised front for barrel support.

The problem arises from the bolt, which is an Izhevsk. On first glance it appeared to be in great condition but now after doing my best to polish to 2500 grit I can see giant chatter marks in the relevant areas, one of the camming ramps has little teeth on the corner my fingernail could easily get caught on. In particular the front area that meets the receiver is almost impossible to polish, it is covered with chatter marks.

I have never shot it and it is causing problems without ammunition, a bad sign.

Sliding back and forth is very smooth, and opening after pre-cocking is great after polishing and cleaning. Closing is very difficult and about halfway down it gets stuck, and then pops closed after the resistance is overcome. Opening is very stiff and happens in a few stages, about half way it requires a solid smack.

In all of this cleaning and polishing the trigger has somehow gotten worse, although it might just need more lube.

I think spring tension is too high, but after installing the bolt without the spring closing was still very difficult in the same way, although opening became perfectly smooth. So the spring alone cannot be at fault, when I screw it in I hear the spring grinding against the channel every few turns, is this normal?

Can I fill the chatter marks with JBWeld or something? Would that be counter intuitive because they indicate that not enough steel was removed? Not sure how I would fix the corner teeth.

I know the bolt can open smooth with the ridiculous marks, although not with the spring requiring cocking, but closing is still inexplicably difficult.

Any advice?

When I get my drill back I will smooth out the firing pin as IV8888 suggests but can't think of anything else to fix this dry situation. If I can't find a different solution I might snip a coil off the spring as well.
 
JB Weld is not hard enough to stay put on a cocking ramp. See if you can find some fine lapping compound, also called valve grinding compound. Put some on the mating ramp surfaces and work the bolt many times, renewing the compound occasionally. The bolt lift should smooth up quickly. You don't want to grind away too much metal, just knock off the high spots. If there is a selection of grades, start with A and finish with 3 or 4A.
 
Get some layout fluid so you can see where the high spots are. Available from Brownells or midway.
 
I will get to that, but don't you think its also the stiff spring and potential cosmo in the lugs on the receiver?

Thanks!
 
I have the opportunity to buy diamond lapping paste of 320, 600, 1200 and 3000 grit, will these do the trick?

It's almost impossible to find lapping compound or valve grinding compound, the finest I could find is 280, at least in an amount less than 1 pound.
 
The first thing you need to do is color everything that moves, everywhere with a black magic marker, candle smoke, or machinists lay-out fluid.

Then cycle the bolt and figure out what is rubbing where.

It is not wise to just indescrimently polish everything, because you can easily make the gun unsafe, or inoperable.

rc
 
OK I will do that. I will color every face that can have contact with a marker and see what happens when I manipulate the bolt. I tried cycling again before doing this though and it seemed like the bolt wasn't touching anything when it goes stuck going down or up halfway, could it be a lug or something further towards the chamber than I can see?

Could the bolt have an internal bind?
 
I did it and all the expected areas came up with the pink dye is used. The receiver internally on the lugs, on the right side which comes in contact close to the bolt handle etc. Additionally there seems to be a burr just passed the left lug inside the receiver requiring a light to see and there are a couple of scratch marks around and accross it. Polishing compound should get rid of this problem and hopefully remove some of the internal bluing which does not belong.

If this works and I have no problems with a real cartridge I wouldn't bother with removing all bluing internally but its something to think about.

Based on what I said would you recommend moving on to the polishing compound? I now know where to put it.
 
Re Post #4 in which you ask if cosmo on the lug could be causing the problem. Have you throughly cleaned the action? I used 1/2 of a can of Gun Scrubber to remove all of the cosmoline from the action and bolt.

I use Clover brand 0000 Fine compound. A little goes a long way.
 
I gave the receiver boiling water baths, mineral spirit baths and ballistol baths. I've been in there with absorbent paper and taken as much as I can out. The bolt is 100% clean of cosmoline. The action is probably 99% clean with what's left in deep recesses around the barrel. I haven't even chambered a round yet so things going on that deep can't be the problem.

I suspect that the big burr surrounded by parallel scratch marks which caught a lot of the dye explain why the bolt just gets stuck halfway down when trying to close or open while fighting spring tension.

I can't find Clover brand in quantities less than a pound, and everybody around here seems to use 280 grit compound at the finest, except for the diamond lapping paste I can get.
 
Napa Canada only has rough stuff in a 1lb jar.

Is it a problem to go with diamond lapping compound at 320 grit and moving up?
 
I can buy some for ~33$, I don't need a lot just a few drops on the lugs, on the burr, and on the faces that contact the receiver.

But just to clarify, can this problem be caused by a dirty chamber? because its only very close to the barrel that there is a bit of dirt and I haven't ecen inserted a round.

lowest price I can get on the JB is 22$, and that won't even do much.
 
Last edited:
Seems unlikely.
But there is no excuse for a dirty sticky chamber.

Wrap some 0000 grade Super-Fine steel wool on a bore brush, chuck it in a cordless drill with a short section of cleaning rod.

Put some bore solvent on it.

And have your way with the chamber & drill.

When you get done there won't be anything left in there the Russians didn't put there on purpose!!

Rc
 
Last edited:
Yes, any oil will work.

Nitro Powder solvent is my choice, but Ballisoil should work as well.

rc
 
OK thank you.

I just gotta vent let me say that this is ridiculously frustrating. I need to go out and buy a 20 gauge brush and that still probably won't fix it, not to mention a drill. At least I can work on the brush this weekend because there's no way the lapping compound will ship over the weekend.
 
Who said anything about a 20 ga bore brush??? :what:

That would be way too big to go in the chamber neck after you wind steel wool around it.

You can do it with a worn-out .30 cal brush, just add more steel wool to fit the chamber.

The brush will be trash when you get done anyway.

Rc
 
Well what I see everyone do on youtube is coat a 20 gauge brush with lapping compound and clean the inside of the receiver/chamber.

But I can just get an ordinary cleaning rod and cover it with steel wool. Still need a drill for that, but I'll get it back soon.
 
But, you said in post #14 that it was dirty 'very close to the barrel'.

Which I took to mean the chamber neck next to the beginning of the rifling??

If that is was what you said, a 20 gage brush will be too big to even get close to reaching it.

You need a bore size brush with 0000 steel wool wrapped on it to even begin to get there.

rc
 
True, I did what I could with rapid twisting of the rod wrapped in the stuff coated with ballistol and got some gunk out of the area as well as lubricated.

After cleaning and cycling up and down about 30 times I have reached the stage with this old Russian girl that I can actually dry cycle while keeping the rifle shouldered, and I'm not that strong. Just takes a bit of aggression, persistence and a smacking. This is all dry, I have no idea what the introduction of a rimmed case will do to this situation :scrutiny: maybe nothing, maybe a small improvement or more likely a disaster.

I feel confidant taking it out and shooting it though, see how the sights are aligned without the bayonet etc. It looks promising but I'll have to see for myself.
 
Well my solvent was ballistol so it is well full of the stuff. It's not too bad actually, if I were a Red Army soldier I would be able to use it in combat, but would probably pick up my dead buddies Mosin or SVT (praise the lawd if you got one of those lol, except this is the USSR, there is no God.).

Shooting should loosen it up and I have a chance to order diamond lapping paste if the additional drill and steel wood doesn't do the trick
 
So, you are in the USSR??

Finish filling out your User Options with your location.

Hard to recommend supplies and where you can get them if you are on the other side of the world!!!

rc
 
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