mosin bolt problem NOT STICKY BOLT

[Riven_Cole]

okay, sorry if this has been asked recently (only found similar problem in a post from 8 years ago and no solution was presented that i saw) or if this is in the wrong area. i also dont mean to seem short or in anyway a know it all, but i dont want to hear that this is sticky bolt syndrome. it is not. too many symptoms dont jive well with that blanket diagnosis, and i have fixed sticky bolt quite a few times, and this bolt is having nothing of it despite my best efforts. anyway, here goes:

when the uncocked bolt is cycled it is extremely (rubber mallet worthy) stiff, but not sticky, and is otherwise pretty smooth. bolt has been completely disassembled upon purchase of rifle and thoroughly cleaned with boiling water and degreaser, after which it was dried and lubed/oiled. problem persisted. chamber was given a given a thorough cleaning as well. i am confident it is not cosmo or fouling. so anyway, if i cycle the bolt when already cocked it cycles just fine. if i cycle the bolt uncocked after i have fired 20 - 30 rounds it is smooth as butter, no stiffness, at least until the gun cools again.
type of ammo fired has no effect. another bolt from a friends mosin works fine in my rifle. my bolt in his rifle has the same issue as it does in mine. already had head space checked/verified as being perfect. gun has no binding points/rough spots in the action or bolt that would explain it. i do notice that the mainspring in the bolt is EXTREMELY stiff compared to other mosins i have handled, when removed from the gun. this thing feels like an easy 30 lb spring compared to my friends mosin bolt spring which was about an 18-21 lb spring. could too much spring tension cause this? also if the firing pin has a slight bend at the spring stop (not sure what the actual name is but it is that raised ring around the pin that the spring pushes) that makes it wobble about 1.5 - 2 mm can that cause binding when it is getting cocked?
keep in mind i have cleaned all the crud from the gun. there was surprisingly little.
thanks for any replies, if you need more data just ask.

p.s. i am coming here for a possible solution to make the gun more... comfortable to shoot (literally need a rubber mallet for handle unless i pull back cocking knob between shots then cycle, i also dont like it when things dont work right) because the only gunsmith within 3 hours of my house wants to hold my rifle for a month plus collect a $75 fee on top of any inflated repair/modification costs just to look at it. i dont trust this guy because he says if he damages the rifle its on me to pay for the repairs, since he has no guarantee at all. he knows he is the only option for most around my town and abuses it greatly.

 

[italy4nra]

Could you try cutting one loop from the main spring to ease the tensionto see if that helps? If it does, cut another two?

 

[Riven_Cole]

i was actually thinking along those lines. i do not currently have the right rotary tool attachment to cut the spring. at least not correctly. oh well they can be had pretty cheap. thanks for the reply

 

[lathedog]

Will your friend loan you his mainspring to try in your bolt? That could isolate your problem or dismiss as a cause.

If it gets smoother after shooting then it is probably not your mainspring. I'm not seeing how a little warmth would make the spring temporarily weaker. But then again I'm not sure what about shooting would make it smoother.

My first thought is a burr or chip in your cocking cam area. I'm not sure what "sticky bolt" means so sorry if that is the same thing. It sounds like the problem is when you make the bolt cock itself thru the angled cam surface. Maybe there is a little chip that gets filled with crud? Sounds weird but I would check with a magnifier.

Also, I know you cleaned your bolt in boiling water and degreaser. Consider that some stuff does not come off with boiling water or degreaser, such as some shellacs, maybe paint, etc. If it was me, I would try soaking in one of these: kerosene, acetone, paint thinner, carb cleaner, or toluene. Whatever you have or can find easily, just try soaking and scrubbing in something a bit more aggressive and then see if you get any improvement. If no joy, then select a different chem and try again.

 

[italy4nra]

I used a leatherman to cut off a coil. No need for a special tool. I ended up taking three coils off, and have not had any misfires (but I do not recommend this).
Also 30lb is standard.

I am thinking through (and looking at my bolt) all the points where there could be resistance when pulling or pushing the bolt....
The bolt friction against the chamber and action surfaces.
The force of the spring
Some sort of resistance or friction at the trigger catch.

That is all I can see.
After 30 shots the bolt cocks the trigger smoothly. This argues for melting crud or breech/action expansion. Wrong bolt size somehow? Your friend has the same type of mosin and therefore has the same result when you swap. Try a third one with a different Mosin type. Ensure headspace clearance before firing. . Bad bolt? Need new bolt.
Could still be crud. I trust you cleaned it fully, but I soaked mine in. solvent overnight, then soaked it in green for a few hours, then went at it with a toothbrush and then boiled.
I also polished all surfaces by fine paper and subsequent automotive paste on the bolt, opening and closing until it was mirrored on all friction spots. Then I repeated the cleaning.
Polishing the bolt at contact points could resolve any slight tolerance issues. You have shot and cleaned many Mosins... so I am just troubleshooting out loud..

It is strange this about the cocked/uncocked.Uncocked, the first lift of the bolt pushes the bolt back, cocking it. The connecting rod slides a fraction of an inch, there is tension from the spring, and possible friction inside the bolt body? Then, cycling it brings the bolt face forward... less tension as the bolt is cocked....

So that narrows is to three points:,1 the spring, for reasons only the lord can fathom loses tension with heat; 2 or clearance between the groove of the bolt body and the wedge of the cocking piece, which for reasons only moses knows are unmatched, but clear sufficiently with heat expansion (when closing the bolt when the spring is cocked, the "wedge" is not in contact with the groove, so no friction.... 3 or 3 a bent firing pin causing friction only on the cocking cycle because it is bent just at the tip (toward the butt, away from the breech).

So your troubleshooting sequence, I think, in order of ease... cut a coil? easier? cut another.
No change? replace firing pin.
No change. It is a bolt assembled from mismatched parts. Buy a new one, or even better, but a new mosin.

 

[Riven_Cole]

thanks for the replies.
used carb cleaner, no change.
went at it with everything i can find that wont damage it. no go
besides the firing pin being slightly bent at the ring that the spring pushes, i notice the sear spring hook(?) where it hits the cocking knob is quite a bit longer than i have seen before. might be part of the issue since the problem is not AS bad in the other mosin. will eventually get a match trigger to take care of that as my current triger is a bit heavy as a result
changing spring will have to wait till next shooting day
as for using a different mosin type: it has the same results more or less in both 91/30 and m44.
force of spring: uhh... almost got killed by the bolt body when my hand slipped while taking off the cocking knob, bolt body actually dented my ceiling. not kidding :banghead:
cleaned/polished/lubed chamber again. no difference.
although after cycling bolt dry except for a little polishing compound on spring/pin it now softens up after 3-5 shots. still a pain for the first few and when it cools. checked chamber for burrs... cant find any, polished a little anyway.
i put polish on the outer curve of firing pin wobble and heard a bit of grinding when working the bolt. very slight sound though. all parts on mosin match. all bolt parts have the last 2 digits of original serial as well. not sure if this is significant.

getting another mosin is not good for now. i like this ones accuracy
thinking this might be a combo of issues that are slowly getting worked out. i actually did not yet cut the spring. tried but broke my wire cutters. no big deal they were cheap. spring isnt even dented
thanks again

 

[srtolly]

I had a similar problem but may not be relevant. My bolt was all mismatched. I used some valve lapping compound (should be able to get at the auto parts store) on the cam area between the cocking piece and bolt body. put the compound between the two and cycled a lot without the trigger installed. fixed my problem.

Also polished all mated parts of the bolt and trigger assembly.

 

[Riven_Cole]

thanks for the reply,
my bolt is matched so far as i can tell. the problem is lessening a bit though since i polished the out edge of the (slight) bend in the firing pin where the spring pushes on it, and i also polished the spring a bit (made it a bit thinner) and it is a bit easier to work. not as good as it can be, but acceptable after a few rounds. now to fix the dent it made in my ceiling. lol