What if Your Mosin Nagant was More Accurate?

Trigger Box Polish

Tweaking your Mosin Nagant rifle for tighter groups is not necessarily the easiest weekend project. However, if you are the motivated type, you can finally take that step past the casual shooter and into the realm of the customized shooting enthusiast. Since I am almost obsessive about getting good groups at the range, my friends wondered why in the world I would buy a beat up old Mosin. I told them I wanted the challenge of taking an Eastern Block bolt gun and outshooting them and their fancy ARs at the range. It might surprise you that with a little ingenuity, it is possible to turn that old Soviet rifle into a finely tuned precision target-blasting machine—sort of. A trigger job can accomplish a great deal. The included trigger on most Mosin Nagants is long, heavy, gritty, and creepy. None of these attributes makes for a very accurate rifle. I imagine the thinking of the designers was to get as many guns in the hands of peasants as they could for the least amount of rubles as possible.

Spring Sear Polishing
Polish the Shaded Areas of the Spring Sear

To help make your peasant gun fit for a Tsar, a trigger job is a good place to start. To perform such a job on a Mosin Nagant, first do a safety check on your Soviet artifact. Open the bolt and make sure the gun is not loaded, and then pull back on the trigger, this will release the bolt, and it should slide out of the back of the receiver. Set the bolt aside and prepare to remove the stock.

To remove the stock, start with the sling. Unsnap the leather straps and set the sling aside. Pull the cleaning rod out from below the barrel. You may have to twist it to remove it completely. The stock should have two retaining bands. Slide these toward the end of the barrel until you can pull off the upper handguard.

Once you remove the upper handguard, you will have to remove two stock screws. A large flathead screwdriver should do the trick. Once the stock screws are out, depress the tab at the bottom of the box magazine, and remove the floorplate and the magazine follower. You can then unscrew and remove the magazine box and trigger guard from the rifle.

Trigger Box Polish
Polish Any Spots Where Metal Rubs

At this point, you may notice that the barrel and receiver are one big piece, at least they should be. You can separate them, but it is not necessary for this application. Take out the barrel/receiver assembly and flip it over so the trigger is facing the ceiling. Take your flathead and remove the sear screw. It may be tight, so some penetrating oil might loosen it up a bit. You will see a trigger hinge pin that attaches the trigger to the receiver. A pencil or punch should easily remove it, just be careful not to lose it! At this point, you should have the sear, pin, and trigger removed from the receiver.

I should use this time to throw in a safety disclaimer. There is always an inherent risk in modifying firearms. If you sand down your spring/sear too much, the cocking knob/firing pin assembly will be unsafe. If you are not sure about what you are doing, simply stop and reassemble your rifle. I’ve seen some people use a Dremel tool for this part of the job, but I don’t recommend it. Instead of a Dremel tool, just use very fine sandpaper or emery cloth, between 600 and 1,000-grit and your fingers. Polish the contact points of the trigger assembly. This includes the upper surface of the spring/sear. On this surface, you will see machine marks running side to side, these marks need to erode down so the sear/spring is smooth. Polish the sides of the sear/spring where it rubs against the inside of the trigger box. After the sear/spring is nice and smooth, polish the inside of the trigger box as well. You can accomplish this by mounting the trigger in a vise and pulling a strip of sandpaper back and forth a number of times until smooth. Also, polish the holes on the trigger where the hinge pin sits. Polishing the hinge pin itself will also help reduce some of the rough feel when pulling the trigger.

Once you are satisfied with your polishing, put a small amount of grease on the contact points, and reassemble your rifle. Cock the bolt and test your rifle for safety. Try dry firing it a few times and if did your job right, you will notice a smoother, lighter pull on your trigger.

Note: Many internet guides will tell you to install a thin metal shim between the sear/spring and the retaining screw. While this will indeed improve your trigger pull, it is easy to overdue it and create an unsafe rifle. If you attempt this, make sure you test your rifle thoroughly for safety before attempting to fire it. The last thing you want to do is fire your weapon when you don’t expect to. As always, make sure you point your muzzle in a safe direction and modify all firearms at your own risk.

Stay tuned for our next article on bedding the barrel to accurize your Mosin Nagant.

The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (17)

  1. Clark, wouldn’t bending the spring sear also shorten sear/trigger engagement? Things could get very light indeed–kind of like a hare trigger. I’m thinking that might not be safe. A little more sear engagement would keep the rifle from firing if the safety were off and the gun dropped. Taking material off the spring sear per this article would maintain the amount of engagement while still lightening the pull. Let me know what you thing. Otherwise, swap away!

    1. I bend the sear spring, but not so much that I do not still get full sear engagement. I have made a graph of Hooke’s law [stress strain curve] showing the two states.

      I can display that pic two ways


  2. Polishing the parts will do no good, nor harm.
    Take a dozen Mosins apart.
    Measure the trigger pull, swap parts and measure all the possible trigger pulls.
    Now start modifying the parts.
    Polishing does nothing.
    Bending the sear does it all… or replace with a Timney is even better.
    Bend the sear only enough so there is still full engagement.
    I made a video

  3. One of the best things I’ve done to mine was to remove the upper hand guard. That alone made a huge difference in the performance of the rifle. As far as ammo goes, I bought 2 cans of surplus when it was cheap and I rarely use it anymore. The stuff I have was like scraping tar off of a roof in wintertime. I mostly use Brown Bear SPs or regular tip ammo and it cleans very easily with just bore foam. I’ve also got some Hornaday match grade that I have yet to try.

    And I would believe it if someone told me they shot a 1.5″ group at 100yds with a Mosin, simply because the best I have done was about 2-2.25″ and I’m nowhere near as good as a lot of people. Although I do have a scope on mine as the iron sights were just plain bad.

  4. Interesting article, can’t wait to get another moison-Nagant to try this out on. It has been my experience that, with Moison-Nagants, as well as other older military bolt-action rifles, changing to commercial ammunition such as Sellers-Beloit, while more expensive, contributes considerably to improved accuracy, as well as eliminating concerns about corrosion. Most of the surplus military ammo kicking around is simply not that good, with the possible exception of the 7.5×55 Swiss and the 6.5×55 Swedish mauser.

  5. I tried shimming the spring, and that only added to the ‘creep’ factor – i.e. I felt creeped-out by the loss of control. The tension spring works smoothly for me, and I will settle for the long trigger pull.

    One problem I have is that I can’t trigger the bolt from half-cocked to closed position when a round is chambered. With my other bolt rifles, this process closes the bolt without firing the round.

    Any advice?

    Thank you for this series. Looking forward to see how you bed the barrel.

    PS- I clean as does Robert. Very easy process.

  6. Does every rifle on the internet shoot 1 1/4″ or better groups? Get real. I’m tired of reading about 600 yard Mosin Nagants and 1000 yd AK’s. Put your money where your mouths are.

  7. Nice article, good description and diagrams.

    Regarding the corrosive primers–there’s good news, and bad news.

    The bad news is you must get the corrosive salts out of the barrel, after every firing session, or they will cause rust.

    The good news is removing the residue is quite easy…just *dampen* (uniformly wet entire patch, just shy of dripping when squeezed) a patch with ordinary tap water and run it thru the bore. Follow with a dry patch, one more damp patch, and another dry…then do your usual bore cleaning procedure.

    No need for extraordinary measures…just a couple of damp patches. But, ya gotta do it–or else!

  8. Both of mine, Finn M39’s with VKT barrels, shoot 1-1/4″ groups at 100 yards. I may have to make these mods though, because the triggers are awful.

  9. Roger,

    I always clean it immediately after shooting when I shoot corrosive ammo. I bring an ammonia based cleaner (Windex) and squirt that down the barrel from the chamber, then spray some WD-40 down the barrel before I give it a proper cleaning. When I get back I pour some boiling water down to clear off the corrosive salts from the primer, then give it the regular treatment, brass brush with copper removing bore cleaner, and patches with gun oil.

  10. How about tips on cleaning this filthy pig. The ammo is highly corrosive and if I don’t clean it atleast 3 times a year it rusts.

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