Non-Bubba Mosin Nagant Accurizing

[mosinmaster]

Hey, so I tried to free float the barrel without having to sand it and it seems to have worked. I shimmed the stock at the rear action screw and just behind the front action screw and just underneath the chamber (behind the rear sight) with 4 slices of aluminum soda can. I can get a piece of paper sliding up from the end of the barrel all the way to the receiver now. Question is, should I also shim the magazine assembly on the bottom of the stock? I heard it can cause feeding issues and I'm not sure whether this will improve accuracy on top of shimming the top side. Rounds feed fine with the shims on top. Should I place a thin 1 pc of aluminum under the magazine floor plate? What purpose does this do?

Recommendations?

When I go to test it, I'll probably shoot it, then take the top hand guard off and try the accuracy. If it improves I may try to wrap some cloth around the barrel at the front barrel band.

Obligatory pics. I used a Coors and Orange Crush can and just taped them together with scotch tape in between each layer.

 

[desporterizer]

Hate to break it to you but the 91/30 barrel is not supposed to be free floating. Snipers actually used to pack their barrels under the hand guard with various materials to tighten the fit. Much like the smle, the long barrel mosins need wood.

 

[mosinmaster]

Yeah I know they did, but those sniper rifles had specific pressure points along the barrel, not random ones due to the stock's shape (in the case of mine). This will allow me to figure out where to pack the barrel, but most 91/30s like to have some pressure around the front barrel band. Anyways, the shims are easily removable so I will try the rifle first without them, and then place them on and see how that works and go from there. It'll save me many trips to the range.

Addendum* It's not completely free floated. At the nose cap, it touches the barrel.

Also, what did the Fins due to captured Soviet 91/30s to make them more accurate?

 

[desporterizer]

Shim the stock where needed to compensate for wood crush, counterbore if needed & screw with the trigger if they had time. Fin capture 91/30's are no more accurate than soviet ones, unless re-barreled. A 1944 tikka barrel is a thing of beauty.
Edit:The finns also got accuracy out of restocking 91/30's with heavier stocks.

 

[mosinmaster]

I did improve my trigger pull weight by bending the sear similar to how the Finns did. I think that will be the largest improvement. I got the shim idea after seeing some Finn rifles and Soviet snipers with brass shims in the stock and oil soaked burlap wrapped around the barrel at the front barrel band.

How is accuracy with a 91/30 after the barrel heats up? I figured floating would prevent it from touching the stock, but then again, since the barrel is so thin, could stock pressure keep the barrel from moving too much? Confused.

 

[mg4201]

If I were you I would bed the action into the stock with bedding compound or jb weld. then you can mess with putting pressure on the barrel knowing that you are only altering one variable.

 

[desporterizer]

How is accuracy with a 91/30 after the barrel heats up? I figured floating would prevent it from touching the stock, but then again, since the barrel is so thin, could stock pressure keep the barrel from moving too much? Confused.

The hotter it gets with a unsupported barrel the bigger the groups get, generally.

 

[stevejones]

So...not too sure what I'm getting from this but do I take it the action and barrel should be bedded?

 

[mosinmaster]

A lot of people tend to shim the receiver to get the barrel floating, and then bed the barrel at the front barrel band to get even pressure there. They say the carbines with their short barrels prefer to be free floated, but the longer 28'' 91/30 barrels prefer to have some even pressure near the end of the barrel (I don't know why since LE No.4Mk1's have floated barrels and so do K31's [perhaps their barrels are heavy barrels]). So I read up on some of the sniper 91/30s and Finn modified rifles and they have brass shims to raise the receiver and float the barrel, then they have leather straps or oil-soaked cloth wrapped 5-7 cm around the barrel at the front barrel band to give that even support at the front. I suppose this allows the barrel to be free floated along it's length and has the necessary packing at the 'sweet spot'. I suppose this is a non-invasive measure of bedding the barrel without having to actually put compound in the barrel channel or corking it (another method).

However! I've seen some group sizes with the bayonet attached and detached, and the ones with the bayonet on have groups closer to the point of aim and are smaller in diameter. Now, I have no idea how the bayonet affects the harmonics of the barrel and how the Soviets were able to get it to work on a mass produced rifle to have the same effect. Is it possible that since the bayonet rotates to the right of the barrel it causes the barrel to be pulled down and to the right affecting the pressure points along the barrel channel?

Regardless, I am very fascinated with the Mosin-Nagant because of the variation from rifle to rifle and the numerous possibilities in making it more accurate. My K-31 gets boring quickly because it shoots so well without mods. I also am learning a lot about what contributes to accuracy and barrel harmonics etc.

One question regarding the Mosin, is does it prefer a certain grain of bullet? I heard the 200gr bullets shoot closer to zero at 100 yards. Any ideas?

 

[mosinmaster]

So...not too sure what I'm getting from this but do I take it the action and barrel should be bedded?

You can bed the barrel, the receiver doesn't necessarily have to be, but it would help since the Mosin stock isn't perfect.

I'm just blabbering on because I want to make the rifle accurate using methods that were used by the Finns and Soviet snipers. Hence, not altering the historical value of the rifle.

 

[mosinmaster]

Here are some pictures of trigger adjustment, shimming, and bedding that I found on the net for the Mosin.

Food for thought.

 

[desporterizer]

Well, lets us know how it works out. I have owned 3 original sniper & none were shimmed or packed. The mint 1944 tula turned out a 3/4 inch group at 100 using cast. I miss that gun.

 

[mosinmaster]

Yeah, I'm hoping that by chance that the gun in it's stock form will be good. But I took some pics of the bore and there's some pitting, albeit there is strong rifling and grooves.

 

[BCRider]

I've saved the pictures in MM's post above. I just wish I could read them....

Most of it is pretty self explanatory. The bit about spacing the magazine so there's 1 to 3mm is an interesting step. As is what appears to be opening up the magazine/trigger guard mortise in the stock so it isn't touching the metal.

The barrel wrap with the tape is the same as the idea I've seen to add a thin layer of cork at around that same position. But in this case it will hold the top heat guard up off the barrel as well.

I'm thinking I may need to get a second MN to set up as a bit of a target rifle now. Which with my eyeballs means setting up some form of target peep sights or adapting to a scope of some sort.

And, of course, getting some reloadable brass and start reloading better ammo than the surplus plinking stuff.

 

[lejarretnoir]

I'm thinking I may need to get a second MN to set up as a bit of a target rifle now. Which with my eyeballs means setting up some form of target peep sights or adapting to a scope of some sort.

And, of course, getting some reloadable brass and start reloading better ammo than the surplus plinking stuff.

This can get contagious BCRider. Once you start it don't end.

 

[BCRider]

Tell me about it! ! ! ! An M44 has already snuck into the cabinet and is making googly eyes at the M91/30 ! ! ! !

Actually that may not be a bad thing. In a couple of months it may lead to a litter of '95 MN revolvers in the bottom of the cabinet....

The M44 came from a shooting buddy that bought it years back and just didn't shoot it at all other than about once a decade. And being a 1953 make it was nice since that's the year I was born.

 

[rdelliott]

I shimmed my M44; trigger and receiver. I used a coke can for shim stock though, which I found kind of amusing. It definitely improved the trigger, and the rifle does seem to shoot more accurately now.