Accurizing A Mosin-Nagant Pt. 2

Discussion in 'Mosin Nagant' started by Joshua M. Smith, Apr 2, 2011.

  1. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    People have been asking me to post my technique for accurizing the Mosin-Nagant, with pictures. Here she is!

    The first thing you want to do is smooth the barrel channel using an appropriate sized dowel rod or socket from a ratchet wrench, wrapped in 320 or so sandpaper. When you are done, you should be able to lay a straight edge along the barrel channel.

    [​IMG]
    Lightly oil the cork bedding on both sides.

    Next, cut cork, lay it in, and lay the barreled action into the stock. Observe whether the barrel lays flat. It may. Now, tighten the front and rear screws to about 50in-lbs. The barrel will probably raise the muzzle quite a bit.

    [​IMG]

    [​IMG]
    Bring lots of ammo and tools to the range. This takes a lot to get right.

    Start placing cork material in the front and rear. You want the barrel to lay as flat as possible when the action screws are tightened.

    On mine, I could not get the barrel to lay perfectly flat, as there is an as-yet undiscovered pressure point someplace in front of the front action screw. It raises just a little bit.


    [​IMG]
    I used business card stock on the top handguard. Oil it well.

    This is not necessarily a bad thing though. It provides an opportunity to add another known pressure point.

    [​IMG]
    Move the front sling mounting point back!

    And this is critical: You have made the barrel bed and handguard one with the barrel. You have a heavy barrel now, for lack of a better term. It's bad for harmonics when you attach anything to the barrel, so move the sling back, especially if you are like me and use the sling to shoot!

    The Finns did something similar to this, and a lot of the time they would cut off the lower handguard. and let it just be on the barrel. This helped with any warpage due to temp extremes and they didn't have to be as precise with their shimming. However, I like the one rigid stock, even if it takes a bit more work.

    I find with this done, I can hold about 1.5MOA, with most rounds in a 0.8MOA cluster -- with surplus ammo. Still working on getting set up to reload.

    Josh
  2. jmeck

    jmeck Scope mount mfgr. Forum Contributor

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    Hey Joshua, You mentioned in part #1 corking the barrel in this manner due to the length and small diameter of the barrel being prone to barrel whip,
    harmonics, heat distortion, ect. I am familiar with this issue with a couple of my rifles. (91/30's). Have you tried this on any carbines? Does a carbine
    suffer from the same problems being its barrel is almost 8 inches shorter?
    Could doing this procedure benefit a 91/30 sporter, being the stock would be considerably shorter and there would be no handguard? A lot less contact points from which to stabilize the barrel. I am currently building a sporter
    with a 23 1/2 inch barrel length and I kind of feel that there may be a sweet spot on barrel length that may also improve accuracy on Mosins. ( could be chasing rabbits there don't know yet) Thanks for posting the pics, I think just about every one is interested in getting their rifles to group more consistent with less flyers.
  3. Cyrano

    Cyrano Resident Curmudgeon Forum Contributor

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    Joshua, do you do anything with pillar bedding? I've wanted to try it but I can't find any how-tos on it that make sense to me. I'm not mechanically adept.
  4. tobnpr

    tobnpr G&G Enthusiast

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    I've heard of using cork to create certain "pressure points" to modify barrel harmonics, but never lying the barrel in a solid bed of cork.

    Cork is one of the best natural insulators known. You have no concern about overheating the barrel?
  5. mrfish1991

    mrfish1991 G&G Newbie

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    I only put about a 1" square of cork as close to the muzzle as I could get it. Then to check that I didnt have any other pressure points, I took a dollar bill (a piece of paper or business card would work...I think you get the idea) and put it under the barrel and ran it along the length. If the bill got stopped somewhere I sanded that area until the bill could pass smoothly under.

    Did this to ensure that the only place the barrel was resting was on the one piece of cork near the muzzle.
  6. unholybeast143

    unholybeast143 G&G Newbie

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    the insulating question is interesting, but i have another that seems more important. due to it's porous nature, cork is way more sensitive to humidity than the wood in the stock. as you heat up the barrel, the cork will dry and shrink, usually very unevenly= different harmonics with each progressive shot. kind of defeats the purpose unless your shooting in dry areas like arizona. if i used that here in michigan, i don't think my groups would be an improvement over just floating the barrel.
    Last edited: Apr 2, 2011
  7. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    Hello,

    My first centerfire rifle was an MN M44. It shat large circles at 50 yards when it heated up. The pressure from the folded bayonet didn't help, but it did it even with the bayonet extended.

    I started developing my technique on it, and got it shooting one hole with S&B at 50 yards.

    Josh
  8. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    Hello,

    I do, but only on rifles that need it. I'm not convinced that the M/N needs it.

    My .22 Savage BTVS does have pillar bedding now.

    All you do is take thick-walled tubing and insert it into the drilled-out screw holes.

    ID should be the size of the screw, while the OD should be the size of of the drilled hole, so that it fits tightly (some use threaded tubes to achieve the same purpose, depending upon whether smooth tubes will let the action move vertically).

    The Mosin-Nagant was designed to use cork and shims -- states so in the earliest manuals, even though it wasn't commonly done by the Russkies.

    And this brings up a pet peeve of mine: the Mosin-Nagant is an accurate rifle, not some random blaster. Set up correctly from the armory, the average groups are 1.5" at 100yds. I am getting 0.8MOA with mine at 80 yards with the majority of cheap military surplus thrown at the target. I got some Brown Bear that I plan on trying here today or tomorrow. The bullet OAL is more closely matched to the 1:9.5" twist, so I expect better accuracy if only for that reason.

    Cheap milsurp ammo and improper maintenance have given the rifle a bad reputation.

    Josh
    Last edited: Apr 2, 2011
  9. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    I do not. First, I oil the cork, and that will help cool the barrel. Second, I do not cork the top, and heat rises.

    The barrel will not get nearly as hot as most semi-automatic .30 calibers, and I've had a tough time getting it as warm as my 1911.

    The receiver and barrel end are great heat sinks, too! :D

    Remember, either which way, the life of a barrel is only two or three seconds! :D

    Josh
  10. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    I need to do that again, with mine. I'm catching up on something near the start of the barrel, I think.

    Josh
  11. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    And this is an excellent question.

    I'm finding that my concepts are not new, but were published in a book well before most of us were born! I'm just rediscovering the ideas.

    I have not read the book, though I should find a copy.

    I am not concerned, mostly because the cork gasket material available these days is impregnated with rubber so it doesn't expand. The stuff at the automotive store -- it's made to run under all sorts of conditions in an engine without adverse effects.

    Even with that said, I oil the barrel channel to keep moisture out of of the stock (use vegetable oil for this; seems less harmful to wood than does petroleum-based), and then I just use gun oil on top of the cork and rub it in.

    Helps with any possible (not probable) overheating issues, too, by acting as a sort-of heat sink.

    Josh
  12. tobnpr

    tobnpr G&G Enthusiast

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    No offense... I don't know you, or anything about you.

    But I'm not buying your claim of consistent .64" groups at 80 yards (.8 MOA) with open sights and surplus ammo. Surplus ammo in and of itself is not capable of that kind of consistency and accuracy.
  13. Vintovka

    Vintovka G&G Newbie

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    hmm... really? with a heavy barrel from a UK-59, modified to fit an MN, USNmars got one to shoot a 1" group at 200 yds, roughly 0.5 MOA, using the 80s Russian light ball. here's the thread (page 7, entry #136):

    http://www.gunandgame.com/forums/mosin-nagant/99576-its-alive-monster-mosin-7.html

    if Josh's modifications couple the the barrel to the stock strongly enough to make it effectively heavy-barreled, which seems to be the claim, i could see him being able to replicate that kind of accuracy. just a thought.
  14. Joshua M. Smith

    Joshua M. Smith G&G Enthusiast

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    Well, Sir, that's your prerogative I guess.

    I'm not the best open sight shooter as I refuse to wear glasses to correct my 20/40 vision, but as long as I can see it, I can hit it.

    Josh
  15. Cell

    Cell G&G Newbie

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    Cool thread but where is part 1?

    Cell
  16. Mooseman684

    Mooseman684 G&G Newbie

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    Im still waiting to see actual 100 yard Targets of that tight of a group.
  17. greenninja5150

    greenninja5150 G&G Newbie

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    Why cork instead of fiberglass/epoxy?
    Last edited: Apr 13, 2011
  18. roggom

    roggom G&G Enthusiast

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  19. gandog56

    gandog56 G&G Enthusiast

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    Because all my life I've been told to put a cork in it?
  20. greenninja5150

    greenninja5150 G&G Newbie

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    Thanks for the interesting read. There's some info to think about there for sure but not an answer to my question. Why cork instead of glass or epoxy.
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