Fat barreled Mosin Nagant build.

[20nickels]

I don't own a bolt action, rarely shoot them and I know little about them so what do I do? I go out and buy a completely stripped Mosin Nagant reciever and a 7.62X54r chambered and threaded fat barrel for the intention of building a "benchrest" gun from the ground up. When It's all said and done I really won't save money over the standard Remchesterby's but my family and I will be able to shoot cheap com-bloc surplus ammo all day at prarie dogs without breaking the bank. Parts so far;
-Stripped Mosin rec. Bought it this way, no history was harmed in the making of this thread.
-Czech UK59 chrome lined machine gun barrel. Don't laugh, you might be surprised at the groups some people are getting from these. Some how a batch of these tubes were screwed up before they drilled for the gas port so they threaded them for the Mosin rec's to try and make some of there $$ back.
-Mosin Bolt complete, off Gunbroker.
-Timney trigger pack.
-Okie coin style headspace guages. Go, No go, and Field.

Future parts;
-Rock Solid mount & bolt handle.
-Scope-TBA.
-Stock, probably a Lowell Designs.

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

First things first. I need to time, torque and headspace the barrel. 54r is a rimmed cartridge so I turned the rim off of one loaded cartridge to see just how sloppy the chamber is. The rimless cartidge sinks .020 deeper into the chamber which brings me to my 1st question;
Should I file the face of the chamber down a bit so it is a tighter chamber or leave it? Thought maybe it would be easier on my brass, not stretching the cases as much, accuracy, etc. What do you think?

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

<span style="font-style: italic">How do you Torque a barrel?</span> Once it is hand tight do you crush it in a bit? Parts of this barrel are way over sized, it weighs 6 1/2 lbs, so I don't mind wrenching on it as it will be turned down to about 7/8" anyway. I have an appointment with a lathe this Sat. the 3rd so I would like to make sure this is the barrel for this receiver before I have the work done. The rec. threads are .940 FWIW. I will have to guesstimate how much the "torqueing" will clock the extractor cut from hand tight.

 

[biffj]

Re: Fat barreled Mosin Nagant build.

Sounds like you need to learn a lot more about gunsmithing before you handle this one. Filing the shoulder or the breechface is a really bad idea. Rimmed cartridges headspace on the rim not the shoulder so use that for setting headspace. You're using a machinegun barrel on a bolt action and that means the headspace specs are much different. MG's don't ever worry about reloading and most of the combloc countries used steel cases in their MG's so pushing the shoulder forward on the fired cases is no biggie. Chambers are normally looser in MG's so you won't likely get much greater accuracy with one of these. A lathe will allow you to work the chamber end of the barrel accurately and thats important. Filing a surface true and flat is pretty tough and if you're not square and straight your barrel will tend to tighten at an angle to the receiver. Try reading some books on gunsmithing and much more will make sense.

Good luck
Frank

 

[Joop]

Re: Fat barreled Mosin Nagant build.

Has the chamber face already been cut for the extractor? IIRC, a lot (or maybe even none) of these barrels were.

 

[biffj]

Re: Fat barreled Mosin Nagant build.

If I was doing this project I'd cut off the rear of the barrel to get rid of the large square threads used on the Vz59 machinegun and also so that I could recut the chamber to a tighter spec. Cut the thread to fit the mosin nagant receiver duplicating the original barrels dimensions. Fit the receiver to the barrel while the barrel is still chucked up in the lathe and mark the location where it stops. Remove the receiver and cut the chamber. Now you can remove the barrel from the lathe and once again install it on the receiver with your barrel and receiver wrench torquing it to whatever spec is proper for the rifle. Check the marks you made while the barrel was in the lathe and if necessary remark it. Now remove the receiver and using your marks as a guide you can cut the extractor groove in the breech face. This is how you insure that the headspace and the clocking are correct. Trying to clock a barrel that hasn't been fitted to this receiver is tough. You can cut the shoulder to get it to the right place but if you do that the breech face may be in the wrong spot so you'll have to trim it and recut the extractor groove in some manner as well as recutting the chamber for proper depth and headspace. Start from scratch on the chamber end and you'll be better off. Files won't work, you'll need a lathe as well.

Frank

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Joop</div><div class="ubbcode-body">Has the chamber face already been cut for the extractor? IIRC, a lot (or maybe even none) of these barrels were. </div></div>
Yes. There is the original UK59 extractor and then they put a Mosin extractor cut centered 120 degrees from it. The UK59 extractor cut is an unsupported weak point but has not been an issue for anyone using these tubes with good brass/ammo.

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

Biff,
The chamber has not been a problem as is. Accuracy reports from people I trust and respect are quite good. I was just wondering if there was any advantage to tightening up the .020 chamber play. Is .020 an excessive figure in a rifle built for accuracy?? You are correct, I should do this while the lathe is available instead of filing it, sometimes I'm tighter than two coats of paint.

 

[Wannashootit]

Re: Fat barreled Mosin Nagant build.

Hope you know what you've gotten yourself into.
Check this out, been discussing it for a few days now with the OP...

http://www.gunandgame.com/forums/mosin-nagant/135869-mosin-heavy-barrel-build.html

Fact is- and I have a really nice Mosin sporter I built that shoots minute of angle- is that if you really find it necessary to re-barrel one of these, you'd be better served getting a match blank, chambered in your favorite flavor (I'd do .308 for bullet variety).

It's a machine gun barrel- not a match grade Shilen...and they take a LOT of work to do it right...

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You can cut the shoulder to get it to the right place</div></div>

There's no shoulder on the barrel the way they machined them.
Crown sucks.
Extractor slot doesn't time (how could it...)

I love modding Mosins, but these are just money/effort that could be better spent with a match grade barrel.

 

[ar15is223]

Re: Fat barreled Mosin Nagant build.

.020 In my opinion is excessive for accuracy, but what technique did you use to find this number? Without machining the extractor cut after fitting the barrel to the action I think there might be a chance that there might not be enough room for the extractor to work. Do you have access to a mill to fix that in case that happens? Cutting material off of the shoulder of the barrel will effect headspace. Do you have access to a chamber reamer to fix that? Im not to sure about cutting a chrome lined chamber with a standard reamer either. These are just a few things to think about.

 

[biffj]

Re: Fat barreled Mosin Nagant build.

I wouldn't run one of my chamber reamers in the chrome chamber. It costs about as much to sharpen as it does to buy one. I'd like to know where these guys are getting Vz59 barrels.....I'd like to get a couple for some Vz59's instead of wasting them on a mosin. Nick is right about buying a blank and starting from scratch if you want a better setup. The work isn't a lot more but the result will likely be a lot better.

Frank

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nick L</div><div class="ubbcode-body">.020 In my opinion is excessive for accuracy, but what technique did you use to find this number? Without machining the extractor cut after fitting the barrel to the action I think there might be a chance that there might not be enough room for the extractor to work. Do you have access to a mill to fix that in case that happens? Cutting material off of the shoulder of the barrel will effect headspace. Do you have access to a chamber reamer to fix that? Im not to sure about cutting a chrome lined chamber with a standard reamer either. These are just a few things to think about.</div></div>
I turned the rim off of one loaded cartridge to see just how sloppy the chamber is. The rimless cartidge sinks .020 deeper into the chamber. What would be considered "acceptable" chamber play?
I will not be reaming a chromed chamber. In theory you could bead blast the chrome out but f it.

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Wannashootit</div><div class="ubbcode-body">Hope you know what you've gotten yourself into.
Check this out, been discussing it for a few days now with the OP...

http://www.gunandgame.com/forums/mosin-nagant/135869-mosin-heavy-barrel-build.html

Fact is- and I have a really nice Mosin sporter I built that shoots minute of angle- is that if you really find it necessary to re-barrel one of these, you'd be better served getting a match blank, chambered in your favorite flavor (I'd do .308 for bullet variety).

It's a machine gun barrel- not a match grade Shilen...and they take a LOT of work to do it right...

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">You can cut the shoulder to get it to the right place</div></div>

There's no shoulder on the barrel the way they machined them.
Crown sucks.
Extractor slot doesn't time (how could it...)

I love modding Mosins, but these are just money/effort that could be better spent with a match grade barrel. </div></div>
That's the best write up yet I've seen of these. If they are bringing that much loot on gunbroker I may just triple my $$ and get out of the UK59 barrel. Though I do think the chrome lining would be cool.
These barrel blanks come to mind to work off of;
http://www.gmriflebarrel.com/productdetail.aspx?id=AK-BLANK
and
http://www.lothar-walther.de/377.php
Scroll down the page. They have a couple in .312 but I like the <span style="font-style: italic">7,65x53Arg Twist-11 $227.00</span>.
I want to stick with .312 bullets. I'm that married to it already. Tks for the replies, keep 'em coming if you have any random thoughts or suggestions.

 

[jwSubMOA]

Re: Fat barreled Mosin Nagant build.

I've done this before. Let me preface by saying I've been a machinist and gunsmith for 20 years. .020" is way too much when you are going through this much trouble,not to mention not good for accuracy. You can't blast the chrome out,the chamber and bore are cut oversize then chrome lined which brings it into spec. If you do not have a very clear understanding of what you are doing do not proceed. After correcting the deep chamber on mine I torqued it and then recut the extractor notch. You will need to set that barrel up between centers to turn it down. Then you have make a sleeve to sandwich between the receiver face and the shoulder where they stopped turning it down on the breech end. Its doable and works quite well, but if you are not an experienced machinist you should leave it alone.

 

[ar15is223]

Re: Fat barreled Mosin Nagant build.

Good luck with your build, the Mosin Nagant isn't the easiest thing to re barrel due to the extractor cut. Also that Greenmountain barrel doesn't have a large diameter, make sure that it is big enough for your aplication

 

[20nickels]

Re: Fat barreled Mosin Nagant build.

What actions are flat bottomed like the Nagant? Heard the Tikka's stocks are a good fit with minimal work for the Nagant. Any others?

 

[jwSubMOA]

Re: Fat barreled Mosin Nagant build.

The older Tikka 595/695 and similar Sako actions,Howa actions are really nice. A Siamese Mauser action would work very well.