Everyone knows about the sticky bolt problem mosins can have and I think that my mosin may have something similar.  When I got the rifle a while back, I removed the cosmoline from the all the parts.  For the barrel/bore I poured hot water down it to heat and help remove the cosmoline, as well as sprayed down it with brake cleaner to get all the cosmoline off. 

Here's the problem I'm having though.  When the rifle is empty and cocked, the bolt easily open and closes.  However, when I dry fire or de-cock the rifle, the bolt suddenly becomes stiff and hard to open, although not stupid hard to open.  When I fire a live round, then I need to smack it open like hell.  After I extract the spend case or re-cock after dry firing, it becomes easy to open and close like before.  If I dry fire, de-cock or live fire the rifle and then pull back on the back of the bolt and cock the bolt that way, the bolt opens with ease as if it were not fired.

I'm thinking that I have some rough machining parts on my bolt that are causing the bolt to become tight after firing, or the spring is just too tight, one or both of these things is what is making it so hard to open.  Greasing some contact points on the bolt didn't help.  Any help and advice from you guys would be appreciated 

Everyone knows about the sticky bolt problem mosins can have and I think that my mosin may have something similar.  When I got the rifle a while back, I removed the cosmoline from the all the parts.  For the barrel/bore I poured hot water down it to heat and help remove the cosmoline, as well as sprayed down it with brake cleaner to get all the cosmoline off. 

Here's the problem I'm having though.  When the rifle is empty and cocked, the bolt easily open and closes.  However, when I dry fire or de-cock the rifle, the bolt suddenly becomes stiff and hard to open, although not stupid hard to open.  When I fire a live round, then I need to smack it open like hell.  After I extract the spend case or re-cock after dry firing, it becomes easy to open and close like before.  If I dry fire, de-cock or live fire the rifle and then pull back on the back of the bolt and cock the bolt that way, the bolt opens with ease as if it were not fired.

I'm thinking that I have some rough machining parts on my bolt that are causing the bolt to become tight after firing, or the spring is just too tight, one or both of these things is what is making it so hard to open.  Greasing some contact points on the bolt didn't help.  Any help and advice from you guys would be appreciated 

These vids may help.

U  could have cosmo build up im the upper and lower corners of where the bolt face meets the the inner receiver wall.  I had this problem with one of my mosins.  Only when it heated up the cosmo would loosen and make it difficult to operate.  I used the boiling water dunk then used a 12 guage bore brush at the end of a power drill.

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I'll try to clean the chamber a bit better.  Thought that hot water and brake cleaner would do the trick, but we'll see.  Weird because even when not firing it needs force to open, but more when firing.  Looking at the bolt there are some pretty rough surfaces where the metal rubs together so maybe I'll try and polish those and sand it down a bit.  Don't really wanna spend much on tools and stuff since the gun doesn't cost much lol.

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You just need a mild abrasive lubricant, old 12ga brush and power drill.

If it gets worse with firing, could be the heat is causing the metal on the bolt to expand.

Is it only when extracting a round/casing or even without? If only when round or casing is in the chamber , watch IV8888's video on the mosin bolt extractor; could be the extracting lips are flared out and need to be pounded in a little bit.

Thanks.  Its only when de-cocking and firing that it locks up.  Chambers just fine. 

One thought I have is to try a different bolt to see if the problem still persists. If the problem persists, I would look to the chamber as the culprit. If it goes away then that may point to the bolt as being the problem.  I would not fire a round with the bolt, however, unless the head space is checked with a gauge. You can use my bolt if you want.

Had a pretty bad binding issue with the bolt from my Type 53.   Watched all the vids, nothing worked.

Tried what Mr. Fartknocker mentioned, swapping bolts... The bolts from all of my other Mosins worked flawlessly.   Compared each bolt component from the working examples to the Type 53's and found the rear fork of the bolt guide rod/connector (where it engages the cocking knob) was slightly bent.   Secured the bad guide rod & gently got it back into shape, matching the good examples.   The Type 53's bolt works as smooth as the others now, guess that slight bend was enough to misalign the entire assembly.

HTH a little, maybe worth at least a look

Boomah

I noticed you said that the bolt can be difficult to open when there is no spent casing in the chamber to extract. Do you find the safety is hard to engage? If the safety is very difficult to engage your firing pin spring is probably very stiff, which would explain why the bolt can be hard to open even with an empty chamber. If the bolt was only binding when you are extracting a spent casing it would likely be caused by residual cosmoline in the chamber.

if the safety is hard to engage then try polishing the firing pin, the spring, and where the spring rides. mine was fine but i tried some upgraded light tension firing pin springs and the bolt and safety both operate with ease now. still get 99% ignition of primers too. the 1% can easily be attributed to the 40 year old ammo

i also did all the polishing and work that was instructed on the video and that helped a lot. besides what iraqvet said in the video i also lathered on some mothers metal polish and went crazy with 0000 steel wool smoothening out everything while polishing and then blued it and soaked it in oil. butter 

Thanks for the replies guys.  I tried lightly polishing the contact areas on the bolt, but it remains the same.  I think it may be the spring, unless wrong.  Haven't fired since initial posting.  Just curious if Nikolai had the same problem back in 1939.  Next time I go to the range I'll test again

I think that the overly stiff firing pin springs that you find on a lot of Mosins are due to poor quality control during the refurbishing process. Seems to me they were either cutting springs too long, or drawing larger gauge wire than necessary when manufacturing springs. It is likely they just stuck whatever springs were laying around after the war in those refurbs to be honest, they were destined to be soaked in cosmoline and crated up anyway.