What calibers can a mosin nagant be changed to?


Eric F
January 14, 2010, 05:14 PM
Say I have just a mosin nagant action, And I wanted something other than 7.62x54. What can The action handle? Where would I find a barrel?

If you enjoyed reading about "What calibers can a mosin nagant be changed to?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
January 14, 2010, 06:27 PM
Honestly, if you're going to the trouble of building up a rifle, I'd start with a better (newer, more precise, better metal) action than a Mosin...

January 14, 2010, 06:39 PM
Take the mosin action, and whack a mauser owner over the head with it, and take his mauser. :D

navyretired 1
January 14, 2010, 07:04 PM
7.62X54 is an excellent hunting round long known as Russian 30-06 and is not readily adaptable to different case sizes. I've seen some pretty neat MN sporters and lots of game have taken with that round starting back in the 1930's.

January 14, 2010, 07:05 PM
I had an idea to do a similar project, but starting with a Type 38 Arisaka receiver. It turned out that it would be a lot more work to build a nice gun from that existing action than to just start from scratch with something more universal. The Mosin action in particular doesn't strike me as something to put much money into.

If you really want to use that receiver, though, it appears that buymilsurp.com has barrels for sale (http://www.buymilsurp.com/mosin-nagant-rifle-barrels-barrels-by-model-condition-c-2_12_2066.html).

My guess would be that the only reasonable caliber to swap to would be .303, because it's rimmed and uses the same diameter bullets. Not an economical swap, though - 54R is a lot cheaper than .303 right now.

January 14, 2010, 07:16 PM
Why would someone want a Mosin action if they had a choice in the matter?

I love the caliber. The history of the rifles is very interesting. The action of the rifle? Well, I like 1KPerDay's answer. :D

January 14, 2010, 07:25 PM
Take the mosin action, and whack a mauser owner over the head with it, and take his mauser.

Well I wouldn't want to hurt family... lol

Eric F
January 14, 2010, 07:27 PM
Oh for pete sake! I just happened to come across a complete mosin nagant action, and was thinking to barrel it to something else. 7.62x54 is hard to reload for based on bullet availbility right now. Also I was thinking 350 rem mag or something larger.

Sure there are better actions but this was free!

January 14, 2010, 07:35 PM
I've heard of them being rebarreled to 500s&w as a single shot

January 14, 2010, 08:27 PM
Yeah I to have heard of people converting to .303 I just tinkered with a 303 in my mosin magazine and it handled it ok, picked up on the extractor with some help, but the conversion doesn't seem to make sense the x54 is easier on brass and just as cheap to reload I think. Certainly surplus ammo is cheaper and although still corrosive I have no problem shooting it but I would not touch cordite. The thing that would take some monkeying to do if it would work at all might be a .356 winchester or a .32 win special. A .32 win would be neat, but it would take a lot of work if it had a shot in hell. The one thing you could surely do if you reload is bore the mosin out and fire form mosin brass to be a blown out straight wall and make shot shells. If I were bored enough and had an old beat up m44 I might give that one a shot.

As far as barrels for mosins already chambered for other calibers I have never seen or heard of them the conversion to .303 can take place because .303 has its shoulder further up the cartridge and I believe you can remove metal from the chamber to accommodate the .303's gently rolling shoulder. That is why my .356 and .32 win ideas are just pipe dreams because they are much shorter cartridges.

I can't remember how the russians attached mosin barrels but it wasn't user friendly, not at all as friendly as a mauser rebarrel job, I think the design just doesn't offer much room to make easy modifications.

Eric F
January 14, 2010, 09:11 PM
I've heard of them being rebarreled to 500s&w as a single shot
Now that would be a rig I have thought about, have any more info? A bolt 500 mag would be cool!

January 14, 2010, 09:28 PM
It depends on how much work you want to do. The rifle is set up for a rimmed cartridge so it would be simpler to go with a rimmed cartridge for a conversion to another caliber so long as the rim size is the same or perhaps just a little smaller. Other wise you need to machine the bolt face also. If you rebarrel, the sky is practically the limit for rimmed cartridges...........Maybe consider the 38-56 WCF, the 6.3X53R Finnish, the 30-40 Kraig, maybe even the 45-70 Govt...........But to what purpose? You can put only so much lipstick on a pig.

January 14, 2010, 10:19 PM
If you absoutely have to have a Mosin in a different caliber, I would look at a rebore to a .33 or .35 wildcat. Cheaper than a quality rebarrel, and no action work necessary.


January 14, 2010, 10:25 PM
I have heard the 45-70 is not too hard - but I agree with the majority - it is a crappy action why not enjoy it with cheap ammo as is - it is not going to be a better action in another calibre and may be an expensive crappy unreliable action in another calibre.

January 15, 2010, 01:07 PM
if you have the skill & equipment just about anything is possible.
i have a 6.5vostock reamer for a mosin project & i have several more on the drawing boards.
i'm going to swage a rim onto 22-250 brass for one rifle & since i just hapen to have a ocagon .416 barrel blank siting in the corner i'm going to make a .416 wildcat based on the 7.62x54r case by blowing the shoulder out. i'll make my own reamer for it.

ptg has the 6.5/7.62x54r(6.5vostock) reamer & the 9.3x53R reamers on file

i've also been thinking about doing a 10,75x68mm since i already load for it.

eventually i'm going to to convert some mosin boltheads to work with the standard .473dia. cases & rethread some aftermarket lr mauser barrels for mosins, sort of a mosin caliber conversion kit.
i think there would be a market for a mosin caliber conversion kit & it wouldn't be hard to do or very expensive.
the bolt heads can be reduced down to .473 by soldering in a bushing, cut the ejector groove slightly deeper reshape the end of the the extractor. i may adapt a sako style extractor to the mosin bolt head.
the shank on a lr mauser barrel can be turned down & rethreaded for a mosin.
epoxy or solder a spacer to take up the slack inside the rear of the magazine.

.308, 7mm mauser, 6.5x55, 250 & 300 savage & .22-250 will fit the magazine with very little modifications, along with many others.

January 15, 2010, 08:13 PM
read about a Finnish Sniper team using a MN action chambered in 300 WinMag...they did pretty well at that sniper comp.

the 416 wildcat would be VERY interesting...make for some serious brush rifle medicine I think, with an 18-20 inch barrel...

January 15, 2010, 09:29 PM
Throw that action away, get a $70 91/30,
$100 for 440 rounds of surplus ammo.
Or just start reloading 54R, there are plenty of .310 bullets from 125 to 200 grain and brass is pretty easy to obtain too.
Making a custom gun on MN action would be not economically wise .
Keep in mind , there are millions of Mosin Nagants in US so this caliber will not fade away as will a lot of wildcats.

harmon rabb
January 16, 2010, 10:44 AM
Oh for pete sake! I just happened to come across a complete mosin nagant action, and was thinking to barrel it to something else. 7.62x54 is hard to reload for based on bullet availbility right now. Also I was thinking 350 rem mag or something larger.

if you buy milsurp, 7.62x54 is so cheap, why do you need to reload?

January 16, 2010, 11:43 AM
7.62x54 is hard to reload for based on bullet availbility right now.

I reload x54r and have had no issues finding bullets. The .311 round is the same used in the Brit .303 and if you buy online, they are easily obtained. Grafs, Powder Valley, Wideners, Midway, all currently have .310, .311, and .312 diameter bullets available. Sierra, Hornady, Speer, PRVI, Remington, Winchester... They all make and sell them. Just bought some 125gr and 180gr Sierra's from PowderValley a couple weeks ago.

But if your dead set on changing caliber then have a go. :)

January 16, 2010, 12:01 PM
I finaly found on Midway USA 7.62x54R Wolf Brand non cor. On a PSL I heard you must use low grain?? the wolf is 148 grain, What is the recommended grain for PSL?

I do not care much for surplus ammo, you have to clean it very well and I would think the Corr salts would get on your cleaning rod and mess up other guns.

Vern Humphrey
January 16, 2010, 12:09 PM
read about a Finnish Sniper team using a MN action chambered in 300 WinMag...they did pretty well at that sniper comp.
So far as I know, the last war Finnland was in was the "Continuation War" with Russia, which ended at least 10 years before the .300 Winchester Mag was developed.

January 16, 2010, 12:18 PM
I don't have the info on-hand, but you can probably find it with some googling: I've read that the Finns were very big into converting MNs to larger calibres for hunting big game (moose and bear?). I believe a lot of them were basically 7.62x54mm wildcats blown out to 9mm and 10mm-ish to use the metric rifle bullets available in Europe.

January 16, 2010, 12:21 PM
So far as I know, the last war Finnland was in was the "Continuation War" with Russia, which ended at least 10 years before the .300 Winchester Mag was developed.
Do they have international sniper competitions during wartime?

Vern Humphrey
January 16, 2010, 12:23 PM
Do they have international sniper competitions during wartime?
Yes. Very serious competitions.

January 16, 2010, 01:38 PM
Making a custom gun on MN action would be not economically wise .

but it would be fun, some of us have the tools & like to tinker.
i have a lathe & over the years i've picked up a lot of nice barrels for around $25-30 so i figure why not try to make something different instead of eating at the trough with everyone else. sure i can get a generic remchester special from wally world but what fun would that be.

Jim Watson
January 16, 2010, 03:14 PM
Agree with MatthewVanitas, the Finns converted a lot of MNs to sporters in various calibers on the 54R case. The 9.3x54R is their version of the ubiquitous European 9.3xwhatever. Then there is the 9x54R Medved, kind of a Dragunov sporter.

Of course if you just want the challenge of gunsmithing the action and forming brass, the sky is the limit.

navyretired 1
January 16, 2010, 05:40 PM
The boxer primer virgin brass cost the same as any other brass from several sources so reloading is easy and you can go from lead (30-30) velocity loads to near 300 Win mag loads in the case and action, if it's in good shape. It's a lot of fun to load all kinds of loads for it.
But as the man said before all the make-up in the world and you still have Miss Piggy.
Can you make a 50 cal browning into a 22 LR, Yes you can but Why, it don't make sense.

January 17, 2010, 01:55 AM
One idea would be pick up a barrel from Green Moutain in 44 or 45 caliber
and then make a rifle in one of the buffalo rifle calibers.

With their 44-40 barrel you could shoot 44 magnum sized bullets (0.430") and chamber the gun for a 44-90 or 44-100 Remington. The 45 caliber barrel would let you chamber it for a 45-100 Sharps. The Moisin action is pretty rugged and would make a good brush rifle in these calibers.

On the other end of the spectrum, you could pick up their 25 cal barrel and do a 246 Purdey. You should be able to load it equal to a 243 Win and it would be a pretty flat shooting, light recoil number.

What type of rifle are you interested in?

Eric F
January 17, 2010, 04:46 PM
Couls the action maybe take a 50-90 sharps?

January 17, 2010, 06:45 PM
Couls the action maybe take a 50-90 sharps?
no, the rim is about .005 larger than the o.d. of the bolt.

January 17, 2010, 07:14 PM
I have not checked my books but if the bolt could be open up enough a 348 Winchester would make a dandy little brush rifle.

January 17, 2010, 11:30 PM
the bolt can be opened up for the 348 win & there are a lot of wildcats based on it.
the 50 alaskan would make a neat mosin, its based on the 348 win case.
the .405 winchester case might work as is.

i guess i'll have to start putting together my remington 1891 22-250 mosin project. i made a couple bushings today to reduce the bolt face down for a .473 case head. i'll solder one on next weekend. i picked up a new tikka bull barrel in 22-250 for about $40 bucks that i'll rethread.
i wonder if i could fit a 550 express in there

January 18, 2010, 12:46 AM
Congrats on your 22-250 build.

Also your idea of a .405 wincester is a great one. Perfect sized base and Green MTN does a cheap 40 cal barrel. Their 40 cal is .401 for a .38-40WCF. Perfect for all the 40cal pistol bullets. Where are you buying $40 barrels?

Sounds like EricF _would_ be interested in a buffalo rifle. Maybe a .50-110 Winchester Express? That has a lot smaller base than the Sharps .50 and I'm looking at 3,300 ft# ME in my book. Probably it would not be a great idea to go much north of that without overstressing the receiver.

BTW, Eric I was thinking a Mike Haas website http://ammoguide.com/
It's great, it's cheap, and you don't need to depend on us old farts to answer your questions.

January 18, 2010, 05:33 AM
In the Combat Arms annual of 2007, David Fortier noticed a Mosin at the 2006 Lapua Sniper Competition in Finland that had been re-stocked and converted to .300 Winchester Magnum.

In the autor's opinion, the coolest rifle at the match was this custom-built Mosin-Nagant in .300 Win. Mag. Driving 155-grain Scenars, it shot well at 1000 meters.
Another quote:
In addition, there was one lone custom rifle built on a Mosin-Nagant action chambered in .300 Win. Mag.

It only had a pic of action and the scope though, not the stock or the whole rifle.

January 18, 2010, 05:35 AM
Here's a picture. Not mine, I found it when I just typed in mosin-nagant 300 win mag. This was the article I mentioned about 30 seconds ago.


January 21, 2010, 11:50 PM
Where are you buying $40 barrels?

gunbroker, sometimes you just get lucky. i got that barrel a few months back & i don't remember exactly what i paid but i think it was right at $40 shipped. its brand new & never been on a rifle.
i watch the barrels on gb at least once a week for deals & around once a month i'll pick up a really nice barrel for around $40 shipped.

if i have time this week end i'll thread the barrel.

i was also thinking about making a 348 case into a semi-rimed case similar to the 220swift.
the .348 case has been made rimless by wildcaters for years so you could just turn the rim to .567 & face .008 off the thickness. then cut the groove a little deeper for the extractor.

January 22, 2010, 08:23 AM
That 6.5x54r seems like just the ticket, if brass can be readily formed for it.

I've wanted to build a cross the course rifle on a nagant action for some time now, in 6.5 caliber.

January 22, 2010, 01:00 PM
You could always buy one of the 14.99 chamber adapters to shoot .32acp and .32 S&W if you want to do the super cheap conversion.

January 22, 2010, 03:35 PM
That 6.5x54r seems like just the ticket, if brass can be readily formed for it.

I've wanted to build a cross the course rifle on a nagant action for some time now, in 6.5 caliber
brass is easily formed & dies are readily available.
to form the brass you start out by necking it down in two steps.
neck it down once with a 7mm neck sizing die then neck it down the rest of the way with a 6.5 neck sizing die. you will then have to ream the neck because it will be to thick.
pacific will grind the reamer with a thicker neck so you don't have to neck turn the brass but their standard 6.5/7.62x54r reamer is ground to the standard 6.5mm neck dimensions.
i paid right a $210 shipped for the reamer & headspace guages.
you can use a standard 7.62x54r die for full length sizing & a 6.5mm neck sizing die for the necks.
the easy way to get the 6.5 & 7mm neck sizing dies to form the cases is to order a fl sizing die in 7mm mag & another in 6.5mm magnum then chuck the die bodies up in a lathe & shorten them all the way to the shoulder.

January 22, 2010, 06:49 PM
here is a picture of a couple of the bolt face bushings for using standard .473 rimless cartridges in a mosin. i still need to solder it in then cut out for the ejector & extractor. they are made from 4140.
the other bolt head is from a bannerman 30-06 conversion.


timneys triggers should be out real soon. they will be around $90
pic of a prototype trigger, they are based on timneys rem 700 triggers.

finished timney trigger

January 22, 2010, 08:10 PM
Dies for the Bench Rest Remington cartridges should work well for resizing 7.62x54R brass. All will have a shorter neck; moving the shoulder forward when fire-formed to increase powder capacity slightly. For a .35 caliber based on the 7.62x54R case, the .357 AutoMag dies might work. There is a .35 caliber wildcat based on the .45-70 called the .35 Greevy Express that will fit in a Mosin and is a ballistic twin to the .35 Whelen.

January 24, 2010, 05:49 PM
the 348 winchester has more case capacity than the 35 greevy express & the rim diameters are within .002".

i finished the bolthead for my 22-250 project.
the bushing is soldered in. i had to slighly deepen the extractor slot. i shimmed the extractor back .010" to make up for the difference in rim thickness then filed the back of the extractor flush with the back of the bolt head.
it will hold a rimless case on the boltface in any direction.
i swaped it out with bolthead on my bannerman 30-06 & cycled a few rounds to test it out & it works just fine.

maybe i'll have time to thread the barrel next week.

May 26, 2010, 02:34 PM
AmmoGuide.com shows the following cartridges based on 7.62 x 54mmR Russian (aka 7.362 x 53mmR Finnish), with cartridge dimensions, and at least one load for each (as a starting point).

6.3x53mmR Finnish
8.2x53mmR Finnish
8.2x53mmR Finnish
.338 M&K
.375 Tyrvaa/.375-53mmR

It would be relatively easy to rebarrel/rebore the Nagant for one these, I would think; if you insist on using that action.

May 28, 2011, 08:56 AM
R.W.Dale said: "I've heard of them being rebarreled to 500s&w as a single shot."

This is because the rim diameter of the 7.62x54R and the .500S&W are the same, so no modification of the bolt is necessary. I am actually going to be setting out on a project to convert a Mosin into a .500 Special 3-shot carbine. No modification to the bolt or receiver, and only a slight reforming of the magazine by just a hair's width. Why .500 Special and not .500 Mag? Because to accomodate the extra length of the magnum round, the scalloped feed guide cuts in the receiver would have to be milled away and hogged out. Doing this then renders it impossible to feed anything upward from the magazine into the bore's axis. But a shorter and stubbier .500 Special feeds just fine. They fit through the top of the receiver to be fed down into the magazine, but are just barely over a single millimeter too wide to actually fit into it. I intend to use a tool to slightly bulge and swage out the inner dimentions of the magazine (the sides are sheet metal, so this will be easy), and trim the stock a little to allow for the new slightly fatter mag body. Throw on a new custom barrel in .500 Special and that should be it. I expect since the only real cost will be the new barrel, this conversion should be under $200. I'm hoping to have, ultimately, a short, sound-suppressed .50 cal. Mosin-Nagant for dirt cheap.

May 28, 2011, 11:58 AM
i'm going to thread and chamber a 9.5x54r this weekend.
its just a 7.62x54r necked up to .375
the very front of the magazine needs to be widened about .030 for it to feed.
it has a 300 grain solid in the pic. to cut the chamber i'll use a standard 7.62x54r reamer with a .375 pilot the use a .375 neck & throat reamer to finish it.
i'm still undecided on whether i'll blow the shoulders out or not

Carl N. Brown
May 28, 2011, 12:22 PM
A Mosin-Nagant in a caliber other than 7.62x54R??

To quote MFP Charlie to MFP Roop in Mad Max: "You're blaspheming again. I don't have to work with a blasphemer."

May 28, 2011, 03:21 PM
Why not a .30-284 for a stock barreled action or the .284 or a 6.5-284 if you're going to rebarrel. A guy on another forum is building one in .30-284 (using .311" bullets) and says the cartridge is an excellent fit in the mag. The bolt will have to be modified like the pics dirtyjim posted.

May 28, 2011, 09:46 PM
For the OP's sake, can we all stop offering senseless, redundant input? One post of discouragement is quite enough. People underestimate the Mosin action, it is simpler than the mauser but as said is harder to adapt to a rimless caliber. It can have excellent accuracy with patience and work, and it is a cheap action to start with.

May 28, 2011, 10:00 PM
The Polish converted a number of Mosins to fire the 7.92x57, or 8mm Mauser, rimless cartridge. I'm pretty sure the biggest investment was simply a redesigned extractor.

May 29, 2011, 04:30 PM
i threaded barrel for my 9.5x54r mosin pig gun today, i'll cut the chamber in a week or two. the barrel is from a howa 375 ruger, i cut the chamber off the rethreaded it. the barrel came out at 20 1/2" and is light for a 375.


for a 6.5 mosin you need one of these

May 29, 2011, 04:46 PM
others here have mentioned the .45-70, found something interesting for the mosin


May 29, 2011, 07:14 PM
Moisins have been rechamberd for 8mm Mauser by Poland, Germany and Austria, rechamber'd in 30-06 in America (Bannernmans are noted)
Into 6.5X54r, 9.5X54R, and quite a few .303 Enfeilds have been rechamber'd to 7.62X54r

Sometimes its just the barrel shank thats reduced and rechameberd, even in 7.62X54r (fix a bum or loose chamber)

You can rebarrels a Mosin into .410 shotgun , 45/70, ect. and quite a few other calibers, although not cost effective, it can be done by any competent gunsmith.

Good luck!

May 31, 2011, 12:32 AM
there is a drop in 22 conversion for it, basically a bushing shaped like a 7.62x54r catridge , neer seen one in person though

as far as changing the gun to a different caliber, i've always wondered if one could be changed to a .410, it would be interesting, but mostl worthless

If you enjoyed reading about "What calibers can a mosin nagant be changed to?" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!