Smooth Mosin bolt hard to open after dry firing

Cosmoline gets into the firing pin channel all the way down to the bottom and you have to be a little creative in getting it out.

Where the locking lugs of the bolt lock into the receiver is challenging too but was probably the part that made the most difference in the operation of the bolt. A friend worked my bolt and said it was the best he had felt in a long time and he's been shooting longer than I've been alive.
 
Headspacing a rimmed-cartridge rifle can be done quite simply with Plastigauge.
This is what mechanics use for bearing clearance measurment.
Insert an empty casing into the chamber & seat it firmly with your finger.
Place a piece of Plastigauge on the down-pointed rifle's casing.
Gently close the oiled bolt.
Extract cartridge, measure Plastigauge & add this to rim thickness.
 
Did you fully disassemble the bolt to its component parts, and clean the cosmoline off all of them, inside and out, including the mainspring? Then you polish the cocking cam with some emery cloth, you are only seeking to remove any burrs, and don't want to change the angles any. Then use a high quality grease to wipe down the mainspring and the cocking cam/lug interface. Also, grease on the locking lugs which engage mortises in the receiver is a good idea. A little grease in the channel where the sear engages the protrusion on the bolt head will typically smooth things up.

I have an ancient bottle of Mobil 1 oil that I dip a solder flux brush into, squeeze out most of the oil, and then dip it in a little tub of gun grease. This makes a slurry of sorts which tends to stay put when in use.

YMMV.
 
You're cocking the firing pin when you're opening the bolt after you dry fire it.
Put a dab of some good quality grease (I've had good luck with Slick-50 wheel
bearing grease) on the cocking cam part of the bolt.
Click to expand...
+1 That was my first thought.
Check the cam surface for obvious rough/wear spots while you're at it.
 
My bolt is very smooth now when the spring is already cocked. I can shoulder it on my left shoulder (the way I shoot) and operate it from there.

However, I seem to be having even more troubles than before otherwise.

Moving it in the rifle is near impossible without cradling the rifle between my legs, using one hand to move the bolt body and using the other to cock it. Operating the safety is equally difficult, as is the last step of reassembly ( pulling the bolt back and rotating 90 degrees). I spent so long on it that I eventually put it back in the box fully assembled but in its uncocked state. I won't be home for a couple of days to mess with it.

Things I did: Greased the entire bolt assembly lightly (helped with opening it in the first place)

Polished the chamber with some Emery cloth (there were some burrs)

Polished the outside (largely aesthetic) parts of the bolt assembly and any that looked like they were having trouble contacting

Sanded the firing pin spring ever so lightly (to bring down weight without snipping a coil)

Bolt operation itself is smoother than ever but no luck with the spring yet... what part is the cocking cam? I haven't been able to find a straight answer on the internet, although I think I have an idea.

Also, there are still some more light scratches appearing on the bolt handle, near the base of the bolt itself. Maybe just wearing in now?
 
I don't know how to post pictures. PM me your email address if you like, so that I can send you pictures showing where the cocking cam is.

-TL
 
Here's a pic-

See that angled cut? That's the ramp that , as you rotate the bolt- moves the firing pin to the rear. Put a dab of some good quality grease on there.
 

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Exactly. But the cam has two inclined planes meeting together. One the one on the bolt body as shown in the picture. The Other one is on the cocking piece, i. e. the safety knob. Both inclined planes need to be smooth. For better operation, polish both planes and put little grease on them.

-TL
 
So... not having my Mosin in front of me, I don't remember there being a clearly defined angled cut there... I remember it being very rounded. I imagine that doesn't help things much.
 
Thanks for the video! I'll have to look at it again when I have my rifle in front of me.

In the meantime, I can order some good oil and some fine grit sandpaper ( I haven't found any finer than 440 in stores) and it will hopefully be there waiting for me when I get home on Monday.

I've done a lot of the steps you describe, but not all of them and not in as much detail. I'll definitely try those fixes and see what happens. I know the tolerances on the Mosin are not great so that probably is a good deal of the problem.

Also, awesome bolt! Looks like you drilled and tapped the receiver for a side mount?
 
Auto parts store is where I get my wet/dry sandpaper. I did do a side mount for the scope out of a Remington 1100 mount. It does need a little shim in the back but is very solid. I'm gonna so another video of it when I out it back together. You might like it.
 
Just checking in.

Finally got time to take it apart today. Looked at the cocking cam (is that what it's called) and polished surfaces on everything. Looked where the surface scratches were appearing. Polished those up in particular as well as any points that have a lot of contact. Even polished the edges of the spring and any burrs on the firing pin. Sprayed everything with CLP and let sit. Reassembled (first time I've done that) and nothing. Still as hard as ever to work.

I did notice the inside of the firing pin spring seemed a little dirty but couldn't work out how to get in there and clean it. Didn't want to introduce water to the situation yet due to possible rust. Maybe denatured alcohol? I use that to clean the grinder chucks at work and it seems to clean metal really well. Seems like the mineral spirit soak didn't work too well, but I wasn't able to do much with them because I couldn't stand working with them for long.

Maybe I should try ordering a new firing pin?

It should be noted that I CAN cock it now and then work the bolt, so at least I have one option when I go to the range to shoot it this weekend. Maybe not the best, but it's something.
 
Use autoparts brake cleaner to get a moderately high-pressure spray of fluid that will dissolve/sweep
away almost anything. Dry it out, then spray it down again with something like WD-40 in this instance.

"Whip-sling" all the excess WD-40 out and you are good to go.
 
There is a point on the bolt, the squared off part where the handle attaches. That part makes contact with the receiver when the bolt is closed, smooth that out too.
 
buymilsurplus is a good resource for extra parts just dont do expedient shipping its worthless


first off id recommend taking the ENTIRE gun apart and do a thorough cleaning of all parts

if bolt is catching disassemble and please post pictures. there are some skilled mosin owners here that can spot the issues, but we need to be able to see them to help.

id personally recommend try dipping the entire bolt in oil and then placing in the gun to work that oil into parts. as a last resort. if all else fails you may need some new parts

another thought could be using high grit sandpaper to sand and polish the area were the bolt goes in. it could be catching a bur and thats could cause the issue
 
First success today!

I left the CLP on overnight as it says that will help the lubrication. I am now able to pull the bolt after each dry fire. It's not necessarily easy, but it is possible and even resembles something smooth when slapped properly.

I disassembled it and sprayed it through with some brake cleaner today. Then more CLP. Then I took a look at the surfaces you described and saw that there was indeed some hang up and some wear spots where the bolt does indeed catch on the receiver. I cleaned all of those surfaces up. Dinner called to me, but I was on the last step of reassembling the bolt after all of the above and hopefully it's even a little bit smoother now.

Thanks for the help guys. I can see the other side of this now.
 
I've owned and shot a lot of Mosins.

Seems that ALL of them have bolts that are relatively hard to operate and take some force to open.

You have to pull the rifle in tight, and almost slap the handle upward with your palm, or otherwise just use a lot of elbow grease.

Great rifle though.
 
Seems that ALL of them have bolts that are relatively hard to operate and take some force to open.
Click to expand...

i beg to differ, my Black lightning has one of the smoothest bolts around since i picked her up(now i looked through dozens of mosins till i found her). also a awesome bore..... i say shes quicker to bolt action than my howa

the truth is its a roll of the dice.

ive seen mosins with great bolts and bad bores, or loose triggers. and a mix in every way , check to make sure its functional till you buy it personally

thats why you test a variety of mosins until you find that "one" you like and feel comfortable with
 
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