Shortening Mosin Nagant barrel...


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Inebriated
July 28, 2012, 11:23 PM
Hey guys, I'm looking for some advice here. I've never shortened a barrel before, but I'm looking to shorten a Mosin (probably a junker... I don't want to do this to anything nice) down to 16" (probably 16.5).

Now, what is the best way to do this, without sending it to a gunsmith? Obviously the quick way is a hack saw, and some file work... but I'm reasonably certain that it isn't the correct way.

So how would you do this, and what tools are necessary?

Also, I'd like to mount an optic... The rear sight base is the easiest way, but since I'm looking at a bent bolt handle already, what are my options for a receiver mount?

Thanks for any input! And no complaining about Bubba'ing the Mosin.

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LJ-MosinFreak-Buck
July 28, 2012, 11:28 PM
Piece of angle-iron that's cut straight to be used as a guide, clamp the barrel into the angle-iron. Saw according the the guide, finish with filing, and you could probably use some sort of dremel tip to reform the crown (I believe while twisting with your hand).

adelbridge
July 29, 2012, 12:21 AM
what are you going to gain from it?

wkumatt
July 29, 2012, 12:31 AM
It's pretty easy. Google potterfield barrel recrown and watch him do it in the video. Then get a brass screw and some lapping compound and you're on your way. You don't have to buy lapping compound from a gunsmith store either, your local auto parts store calls it valve lapping compound.

Enjoy your fireball.

Sent from my PB99400 using Tapatalk 2

Inebriated
July 29, 2012, 12:31 AM
Piece of angle-iron that's cut straight to be used as a guide, clamp the barrel into the angle-iron. Saw according the the guide, finish with filing, and you could probably use some sort of dremel tip to reform the crown (I believe while twisting with your hand).

Sounds easy enough. How does doing the crown that way compare to, say, a crown face tool?

what are you going to gain from it?

A range toy, and a handy little deer or hog rifle.

What does it matter?

It's pretty easy. Google potterfield barrel recrown and watch him do it in the video. Then get a brass screw and some lapping compound and you're on your way. You don't have to buy lapping compound from a gunsmith store either, your local auto parts store calls it valve lapping compound.

Enjoy your fireball.

Sent from my PB99400 using Tapatalk 2

I actually JUST saw that, and I'm thinking I'll go that route. It's easy, cheap, and well... Potterfield recommends it.

And lol @ the fireball.

ShadowsEye
July 29, 2012, 12:34 AM
My Mosin crown was accomplished with a belt sander to true the barrel a dremel to chamfer and a buffing wheel with black emery to completely remove the sanding marks. Also, don't forget to re-blue the exposed steel!

http://farm8.staticflickr.com/7259/7666341128_d60cc6bb92_b.jpg

I chose to cut mine to 20" which is what was issued with the M44, the M44 has the same rifling as the 91/30, I'm sure 16 will shoot, but the wasted energy in 20" is pretty bad with surplus ammo- (re: giant fireball of powder still burning after the bullet leaves the barrel),

LJ-MosinFreak-Buck
July 29, 2012, 12:34 AM
How does doing the crown that way compare to, say, a crown face tool?

No idea, haven't done it personally (crowning). The brass screw is also another good way to do it.

Inebriated
July 29, 2012, 12:40 AM
My Mosin crown was accomplished with a belt sander to true the barrel a dremel to chamfer and a buffing wheel with black emery to completely remove the sanding marks. Also, don't forget to re-blue the exposed steel!



I chose to cut mine to 20" which is what was issued with the M44, the M44 has the same rifling as the 91/30, I'm sure 16 will shoot, but the wasted energy in 20" is pretty bad with surplus ammo- (re: giant fireball of powder still burning after the bullet leaves the barrel),

I'm thinking that for range time, that's fine. For hunting, I think any of the quality SP loads out there would work just fine (of course if they don't, I can always JUST use it for the range).

And that looks like a good job!

No idea, haven't done it personally (crowning). The brass screw is also another good way to do it.

Well then I'll be sure to let you know how it goes!

LJ-MosinFreak-Buck
July 29, 2012, 12:43 AM
Please do, I'm going to be working up a custom Mosin here soon, but I'm going a different way than most.

Inebriated
July 29, 2012, 12:45 AM
Please do, I'm going to be working up a custom Mosin here soon, but I'm going a different way than most.

I'll probably go pick the rifle up next week, and probably cut it that day. So expect a PM in about a week. Or look for a post here. Depends on how well it goes lol.

LJ-MosinFreak-Buck
July 29, 2012, 12:48 AM
lol, well I'm probably going to have a barrel made from one of the respectable companies out there and have it set for a bore diameter that can use the .308" bullets instead of the .310-311. Better options for hand-loading then.

Inebriated
July 29, 2012, 12:52 AM
Now that sounds like a pretty good plan. I'm not into loading, but that would make working up a hunting/target load a lot easier.

LJ-MosinFreak-Buck
July 29, 2012, 01:00 AM
That's what I figured in the brainstorming part of the project. I'm going to start loading for 7.5 Swiss, x54r, and 8mm Mauser, so lol. Possibly .308, too, because I'm thinking about getting a .308 barrel for my Savage 110.

Inebriated
July 29, 2012, 01:02 AM
I need to start loading. Mostly because .45 ACP is getting so expensive.

LJ-MosinFreak-Buck
July 29, 2012, 01:15 AM
I hear ya there. Thinking about pistol calibers, too, but I'll wait on that for a while. 9mm and .40 are both still fairly cheap, so.

TurtlePhish
July 29, 2012, 01:35 AM
If you look around at places like Brownells, Midway, and Accumounts you'll be able to find recrowning tools that come with pilots for different bore diameters. That's the best, most accurate way to crown the barrel short of turning the whole thing in a lathe. The tool itself costs a bit, but it'll work for any rifle with the proper pilot, and pilots aren't expensive. Good thing to have IMO.

headoftheholler
July 29, 2012, 11:37 AM
If you look around at places like Brownells, Midway, and Accumounts you'll be able to find recrowning tools that come with pilots for different bore diameters. That's the best, most accurate way to crown the barrel short of turning the whole thing in a lathe. The tool itself costs a bit, but it'll work for any rifle with the proper pilot, and pilots aren't expensive. Good thing to have IMO.
For what the average shadetree gun tinkerer would need, the cost of proper recrowning tools doesn't make sense. Either do the brass screw method which has been used for close to 100 years now or send it to a gunsmith to do a target crown. When I cut my Tikka mosin sporter barrel I used the angle iron/hacksaw method. Level off with a file and sandpaper and brass screw crown. For what the brass screw costs ($1.25) its worth trying, if accuracy is not up to expectations afterwords, you are out a dollar and you send it to a proper gunsmith.

Inebriated
July 29, 2012, 02:29 PM
headoftheholler, you just summed up my thoughts. The brass screw is cheap to try, and if it works, it cost a dollar.

TutrlePhish, if I were to pay as much for the crowning tool, I'd probably send her off to a gunsmith. Though I do agree, it's nice to have the proper tools.

LJ-MosinFreak-Buck
July 29, 2012, 05:38 PM
The proper tools are a good buy if you do that kind of work often


~On The Road Again...~

Tempest 455
July 29, 2012, 06:44 PM
I did mine at 22" and that seems ideal between fireball and accuracy.

http://www.youtube.com/watch?v=3-VlE1sUMbQ&feature=plcp

http://www.youtube.com/watch?v=KrFc4Eu594A&feature=plcp

http://www.youtube.com/watch?v=wwxI0xwybjQ&feature=plcp

poolingmyignorance
July 29, 2012, 11:16 PM
You'll lose 25.6fps per inch you chop and gain 1db of noise.
At a maximal velocity of some 2800fps @ 28.75" and a minumum of 2500fps at 16.75"
The "rule of thumb" 50fps per inch of barrel length doesn't seem to be applied with this shell. (atleast not Milsurp).
I cut mine down to 16.89" and after 11 degree target crown.
All my numbers are sourced from this article:
http://honors.usf.edu/documents/Thesis/U82488180.pdf

Heres a break down on exactly what I did to mine. It really cleaned up the groupings of this rifle.
http://www.thehighroad.org/showthread.php?t=668429
A lathe isn't necessary for crowning as they sell hand tools for it at brownells.

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