Whats up with my Mosin Nagant?

Had a problem pop up yesterday with a MN,and Id like you fellas thoughts please.
Ok,it was unfired by me,recently bought new,in cosmoline. Cleaned her up really nice,bore looks unfired.All matching numbers...real clean,sharp rifle.
Now,as I do all my weapons,Ive been dry firing it a lot. All a sudden yesterday,BEFORE any live fire had been done,the bolt became VERY VERY hard to open,after I would dry fire it. Im full aware of the sticky chamber/laquer ammo problem,this is not what Im talking about.
The bolt cycles very easily/smoothly while cocked,but drop the hammer on a empty chamber,and ita a mofo to open again. Ive felt aroung the chamber and feel no burrs or anything outta place,and a visual of same confirms that too.
So...thoughts and opinions on cause and remedy appreciated!!

Did you disassemble the bolt while cleaning out the Cosmo? If you didn't you should and if you did you may want to do it again.

That's all I have to offer and probably doesn't help.

I will second what Garufa said.

I have never heard of a sticky bolt from dry firing. Sounds like cosmo in the bolt.

Another idea....

I would completey disassemble the thing and make sure there is no goop down in the internal workings, as crude as they are.

Here's how I did mine: Collecting and Shooting the Military Surplus Rifle (2006) - Surplusrifle.com

Thanks guys...I assure all there is no cosmoline anywhere on the rifle. Bolt has been stripped three times now,including just now. Problem is getting worse. i know what it AINT:
1.Bolt is assembled correctly.
2.No cosmoline/laquer at all on weapon.
3.Nothing looks out of the ordinary.
So,Im still open to ideas as to why the bolt on this rifle is so hard to open after dry firing on an empty chamber.

I am not doubting you at all on the cosmo thing.

have you shined a light down the chamber. It is possible there is cosmoline caked up against the face of the chamber. It may well appear to look like metal, but in reality is 50 year old cosmo sitting in there. Just a thought or a grasp at a straw.

Thanks for the suggestion Mike.357...but I SWEAR there aint no cosmoline on this rifle. And again,this problem just started Saturday,after me dry firing it for the past few weeks. Just out of the blue started.
Yes,Ive TRIPLE DOUBLE QUADRIPLE checked chamber,bolt WHOLE RIFLE and NO cosmoline.

if you look down to the chamber you should see a notch in the face of it. My Mosin is buried in the safe and I am not digging it out but I believe the notch would be at about 1 or 2 oclock.(I might be way wrong about the postion of the notch but there is a notch.) I only mention cosmo there because a Mosin Nagant I previously owned was cosmo free( so I thought) and there was some cosmoline caked up like it was welded in place against the face of the chamber.

Maybe check these websites out.
7.62x54r.net
Mosin Nagant

I am out of ideas and information. Good luck

PS: Just thought of one other thing. The nob on the ass end of the bolt is adjustable. Is it possible this has slipped out of place. The first website I mentioned in this post probably has information in the nob and the proper position of it. Again grasping at straws for you.

I dryfire mine but I use a spent case in the chamber. I know its impossible unless you shot it first....but I'm just sayin'.

...Anyway. Is your firing pin flush with the end of the bolt rear, where the scribe mark and firing pin threads line up? the only way I'd forsee any problems in bolt cycling is high spring tension, or if the cam is burred or the trigger doesn't reset forward enough where it binds under the bolt "carrier".

Is it just hard to open period (rotate the bolt upwards), or to pull it back after opening. It may be something simple like lube or technique. I read somewhere that using your left hand with the palm on the reciever and the fingers over the top of the bolt gets it done with almost no effort. That's apparently how the Soviet soldiers did it b/c the MN was mainly used as a trench rifle under supported positions....

Just one suggestion......Take the action out of the stock and make sure the large screw holding the trigger assembly in the action isn't loose and there are no broken parts in the trigger assembly. The trigger has to reset when you raise the bolt handle, so if something in the trigger is broken or reassembled incorrectly or left loose, it may not want to let the bolt reset it, which would make raising the bolt handle a real itchbay. You might even have a broken trigger spring, which I believe could cause hard bolt lift. Just a thought.

Jer