My son recently bought a Mosin Nagant, and I bought 2 cans of surplus ammo to shoot through it. The rifle is pretty accurate but the bolt is very difficult to open after firing. Does anyone out there have an idea why. The shells load easy, and the bolt slides smoothly, but after each shot, it is difficult to get the bolt to turn the last 1/8 inch in order to pull the bolt back. Once we do get it turned, the shell ejects just fine. Any clues?
Mosin nagant bolt problem
- Thread starter Carman
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winmag
Well-Known Member
Could be excess headspace issue maybe. As the brass expands the shoulder would "slam" into the front of the chamber. This could cause hard bolt lift toward the end of the bolt throw upon extraction. Maybe it could be a sloppy chamber too, & it could be swelling the case slightly at the base, where the case head meets the case wall. Those rifles weren't exactly known for tight tolerances.
I'm just taking a shot in the dark here. I'm no gunsmith.
I'm just taking a shot in the dark here. I'm no gunsmith.
Thanks for the reply...that is something I will get checked out next. I read on another site that the number one cause is a layer of varnish that forms in the chamber from the cosmoline. The more you shoot it, the more this film heats up and becomes sticky...almost like glue. I just sprayed some easy off into the chamber and then used a chamber brush vigorously and then ran some swabs with solvent through it. The swabs came out VERY sticky. I repeated until the swabs came out clean and no longer had a sticky feeling. The chamber now looks amazingly better. I will go shoot it tomorrow and see how it does. The particular site where I read about this says that the problem gets worse the more you shoot it (which it did) because this varnish heats up more and just gets more sticky with each shot. If it is better tomorrow, I will clean it again while the barrel is warm. If I continue to see improvement then I will continue down this path. If it doesn't improve, I will make a trip to the gunsmith to check the headspace. I think the varnish is the problem as I went out and got a couple of the spent casings and they definitely feel sticky.
winmag
Well-Known Member
That makes perfect sense.
Leave it to me to "forget to check the mower for gas" before I jumped to another solution....
Old ammo can also have such tarnished brass that it sticks, even without cosmoline. Good call on giving the chamber a good scrubbing. You probably just solved your problem.
You may want to polish up the brass a bit too.
Leave it to me to "forget to check the mower for gas" before I jumped to another solution....
Old ammo can also have such tarnished brass that it sticks, even without cosmoline. Good call on giving the chamber a good scrubbing. You probably just solved your problem.
You may want to polish up the brass a bit too.
Mada
Well-Known Member
I might be a lil late, but I think its from the case expanding after firing that is causing the sticky bolt.
I had the same problem and now I use Zinc plated cartridges, problem fixed
I had the same problem and now I use Zinc plated cartridges, problem fixed
The varnish off of steel cased ammo will melt and cause the gumming up also. If you are using milsurp ammo be sure and clean the bore with water to get rid of the salts from the corrosive priming even if the seller of the ammo says it is not corrosive most of it is. Also the way that the bolt is designed on the M/N it does not have a lot of torque for lifting and opening that last little bit. Standard training was to lift the bolt up to 2 o'clock and then slap the bolt with the palm of the hand to open it up the rest of the way. Watch the movie Enemy At the Gates. In the part where they are in the fountain and he is shooting the German taking a shower and the others around him you can see him operate the bolt like that.
Slug the bore of your rifle with a lead .315 diameter muzzle loader ball or a fishing sinker about that size by driving it from the chamber end out the muzzle with wooden dowel rod pieces cut 6 to 8 inches long dropped on top of each other. Start the ball with the steel cleaning rod and a hammer. Measure between the high spots which will be the groove diameter of your bore. If it comes out .310 to .3105 use .311 diameter bullets. If it comes out between .3105 and .3115 use .312 diameter bullets. They like heavy bullets 174 to 180 gr really well. Best load that I have ever found that shoots great in all models of M/N which I have most of them. 50 grs AA 4350, CCI 200 primer, Prvi or Laupa case, .311 diameter Sierra 174 gr Match King or 180 SP OAL 3.000. If you need a .312 diameter bullet use the Hornady 174 RNSP OAL 2.790 and this is important to best accuracy. Use a Lee Factory Crimp Die on all loads.
You can use shims inserted between the action and the stock where the action screws go to raise the action just a little bit and then place a piece of felt cloth 1 inch wide by 6 to 8 inches long wrapped like you would put grip tape on a baseball bat around the barrel about 3 inches back of where it exits the forearm wrapping back toward the action. Place some light oil on this felt which will deter any moisture being held in it and rusting your barrel. This will float the barrel and aline it in the stock. The Finns did this with their sniper rifles to make them more accurate and it works. I have some of the M/Ns that are tack drivers. These rifles look like a farm tool made by a blacksmith but once you get them tuned up they will shoot. Have fun.
Slug the bore of your rifle with a lead .315 diameter muzzle loader ball or a fishing sinker about that size by driving it from the chamber end out the muzzle with wooden dowel rod pieces cut 6 to 8 inches long dropped on top of each other. Start the ball with the steel cleaning rod and a hammer. Measure between the high spots which will be the groove diameter of your bore. If it comes out .310 to .3105 use .311 diameter bullets. If it comes out between .3105 and .3115 use .312 diameter bullets. They like heavy bullets 174 to 180 gr really well. Best load that I have ever found that shoots great in all models of M/N which I have most of them. 50 grs AA 4350, CCI 200 primer, Prvi or Laupa case, .311 diameter Sierra 174 gr Match King or 180 SP OAL 3.000. If you need a .312 diameter bullet use the Hornady 174 RNSP OAL 2.790 and this is important to best accuracy. Use a Lee Factory Crimp Die on all loads.
You can use shims inserted between the action and the stock where the action screws go to raise the action just a little bit and then place a piece of felt cloth 1 inch wide by 6 to 8 inches long wrapped like you would put grip tape on a baseball bat around the barrel about 3 inches back of where it exits the forearm wrapping back toward the action. Place some light oil on this felt which will deter any moisture being held in it and rusting your barrel. This will float the barrel and aline it in the stock. The Finns did this with their sniper rifles to make them more accurate and it works. I have some of the M/Ns that are tack drivers. These rifles look like a farm tool made by a blacksmith but once you get them tuned up they will shoot. Have fun.
I am pretty certain that the problem is varnish buildup inside the chamber, either from the cosmoline and/or lacquer from the ammo. I sprayed some easy off oven cleaner in the chamber and let it set about 5 minutes. Then I ran a chamber brush in a gave it a good scrubbing. Then I ran solvent soaked patches in and they came out not only nasty, but they were VERY sticky. The chamber and bore are very clean now. If I shoot the ammo and at first, it functions ok, and then gets worse the more I shoot, then I will know that it is the ammo. If it continues to function fine, then I will know that it was a varnish buildup from the cosmoline. These seem to be the two most prevalent problems with the bolt become difficult to operate. I had the headspace and chamber tolerance checked this morning, so I am pretty sure it is lacquer from the ammo or the chamber just needed a good cleaning.
If you check the screw on the back of the bolt safety and see if it goes straight up and down or is turned off to one side. It needs to be straight up and down to the witness mark or it can cause a bolt to close hard on the Mosin Nagant. They also close hard to begin with but check that and see if it is the problem. Also the springs in the extractor are super tough and I have had a few that just would not slip over the case head and would not let the bolt close. Gun smith took care of that problem by shortening up the spring.
but check that and see if it is the problem. Also the springs in the extractor are super tough and I have had a few that just would not slip over the case head and would not let the bolt close. Gun smith took care of that problem by shortening up the spring.Easy off oven cleaner sprayed into the chamber and then a good scrubbing with a chamber brush solved the problem. Fired 40 rounds through it yesterday and it never got sticky. 50 years of sitting in cosmoline left a layer of hardened crust in the chamber and the easy off got rid of it in 10 minutes. I recommend using it to anyone buying one of these rifles. This rifle is incredibly accurate too. Was knocking down bowling pins at 300 yards.
