Feasibility...Mosin-nagant rebarrel to .348 win.

[Clipper]

Always wanted a .348, love M-Ns, and I hate showing up with the same stuff everybody else has. The difference in rim diameter looks doable, but my M-N sporter (not the one I'd use) is at my buddies house, so I'm not able to do any magazine measurements now.

Do any of you gunsmith types see any obvious problems?

Thanks

BTW, the concept is for a full-stock, express sighted, butterknife bolt handled carbine, around 19" barrel.

And would it be more economical to rebore the existing barrel, or replace it entirely?

 

[rcmodel]

Other then needing your tooth fillings re-tamped after you shoot it in a mossy stock you mean?

The barrel shank is .980" 16V TPI.

The 7.62 Russian case is .489 at the rim.
.348 Win = .535".

Should be enough barrel shank thickness left to handle the pressure.

Rim is much bigger on the .348, so bolt face, extractor, ejector, mag & feeding problems should be expected.

But it's really too late tonight to do the exact research down to the last knats kapootie.

Only obvous problem I see besides the excessive recoil would be the cost.

Unless you have a lathe and other gunsmith equipment to re-barrel it yourself?
You can go buy a brand new .375 H&H rifle cheaper.

rc

 

[dirtyjim]

you will have to modify the magazine & the bolt face.
basically on the magazine the sides will need to be cut out for the rim and new metal welded in giving it enough clearance, you can just do the cuts under the wood for three down. the front of the magazine may need widened a little bit but it should clear. i had to widen the front of the magazine on my 375x54r by about .020".
the lip on the bolt face will also need to be recut for the larger rim diameter and it leaves a very thin lip.
if you handload & have access to a lathe the .348 rimless would be just about perfect.
the rim is cut off and a groove for the extractor is made. there are a lot of rimless and semi-rimmed wildcats based on the 348 case

 

[Clipper]

I'm a retired toolmaker, and so is my #1 shooting buddy. I have a 12X36 atlas, and a 6x12 Boyar-shultz surface grinder. I have a CNC mill, and he has a manual. I also have my own welding equipment, so I intend to do most, if not all of my own machining and welding.

BTW, the stock is always the first part of a M-N that I trash! I'll be most likely using a Richards old classic full-length stock blank for a M-S look. The finished product should be a kick butt woods rifle for deer, black bear and perhaps elk in thick woods.

The idea of trimming the case rims would likely be the best idea. I didn't even think of that, though I know it is done on some wildcats. Like I say, it's just a concept I'm kicking around, 'cause I'm bored, and I'm on a mission to have the coolest M-N in the woods...

 

[willypete]

rcmodel, you posted base diameter, not rim diameter.

7.62x54r rim diameter is 14.4 mm (.567"); .348 Winchester rim diameter is .610".

Clipper, I've thought of doing this with a .45-70 and turning down the rims to match the bolt face. I lack your skill and equipment, but this sounds like a great project.

http://pirate4x4.com/forum/showthread.php?t=926887&highlight=45+70+mosin

I've been following this thread on another forum. It's interesting, to say the least.

 

[Clipper]

Well, as RC said, I'm a little trepidacious about recoil in what will be such a light rifle in that caliber. My grandad said his M-71 deluxe was quite a thumper, even with a recoil pad, and those guns were pretty heavy. My uncle had the standard '71 with the metal buttplate, and refused to shoot it more than the once-a-year at a deer. Said he'd be bruised for a week. This will for sure get the shotgun recoil pad treatment...Pigs are becoming a problem in MI, and I'll bet a .348 would really ruin a piggie's day.

 

[dirtyjim]

i shoot quite a few big bores and the best thing you can do is shoot them from a standing rest instead of off the bench. our standing rest is made from two pieces of pipe about 3' long, an old wheel, two studs with wingnuts, a 6x6 inch piece of 1/8" plate and a front bag. find two pieces of pipe one around 1 1/2" and the other around 1 3/8", you'll want one to be able to fit inside the other but not real loose. weld the larger pipe to the wheel and drill & tap the other end of the pipe thats welded to the wheel for two 3/8" studs to hold the other pipe at whatever height works best for you. weld the 6x6 plate to the other pipe and attach the bag to it and you have a portable standing rest. i can easily shot three times as long from a standing rest as i can from a bench.

if you go about halfway down this page it shows a 45-70 build being done keeping more of a military look.

here is a czech builder who has built what i would consider the best mosin sporter i've seen so far. 45-70 octagon to halfround barrel, claw mounts, single set trigger, butterknife bolt handle and a german style stock with side panels. the only thing its missing is a forend wedge. the page is in czech so you'll have to use a translator if you don't read czech

 

[Clipper]

That Czech rifle (except for that unfortunate "cheeked" stock) is really nice. I don't know if it's going to be possible, but I want to keep the original M-N barrel profile, which would probably qualify as a 'featherweight' barrel when it is only 19" long and has a .348" hole instead of a .311" hole through it. This will make the gun a lot lighter than I might later wish it was, but I've always been a shorter, smaller & lighter is better kind of guy. I also want to put an express-rifle style quarter rib and 3 lyman folding leaf sights on it, and it appears that I'll have to make that myself, since I can't find one online.

 

[dirtyjim]

the original barrels have been rebored to 9.3mm so it can be done. it usually cost around $220-250 for a rebore and little more to cut the chamber.
the rib will have to be made to fit the barrel contour, dakota used to sell a generic rib that could be adapted to most barrel but it would still be cheaper to make your own.
one of the guys i know that makes quarter ribs make a mold from the barrel using epoxy then uses his mill & a tracing fixture cut the contour of the mold to a piece of 9/16x9/16 square stock then cuts the dovetail for necg sights.

i've also heard of people adapting the ruger #1 rib to other rifles

 

[rcmodel]

rcmodel, you posted base diameter, not rim diameter.

Yes, I did.

We were talking about how much metal would be left in the barrel shank after reaming a .348 chamber in it.
So base dia was the measurement we needed to know.

rc

 

[Clipper]

OK, I've been taking some measurements, and I think this can work with a minimum of tweaking besides the rebore. What I was wondering though, is if the chamber reamer will have the rim face or if that is done seperately. I plan to turn the .348's rim to the size of the 7.62, making a semi-rimmed case, and I wonder if i'm gonna have to get a custom reamer made, or is there a 348 rimless reamer available?

 

[rcmodel]

Reamers for rimmed cartridges also cut the rim if necessary.
http://www.midwayusa.com/product/887361/ptg-solid-pilot-chamber-finish-reamer-348-winchester

rc

 

[Clipper]

Thanks guys, especially you, Dirtyjim...Between Clearwater reboring and Pacific Tool & Gauge, I have all my ducks in a row for this build. Now for the money part...

 

[barnetmill]

dirtyjim
basically on the magazine the sides will need to be cut out for the rim and new metal welded in giving it enough clearance, you can just do the cuts under the wood for three down. the front of the magazine may need widened a little bit but it should clear. i had to widen the front of the magazine on my 375x54r by about .020".
the lip on the bolt face will also need to be recut for the larger rim diameter and it leaves a very thin lip.

You probably know better than me, but just looking at the inner surfaces of the receiver rails of my mosin, they are set up for feeding the rimmed 7.62x54. There also some sort of springy things there that serve as an ejector and also prevent rimlock. Closing the bolt displaces these to the side allowing the next round to feed in toward the top. Feeding rimmed cases in box magazines requires a lot of thought. If the .348 case is not compatible it looks like some tricky machining could be involved. The 7.62 russian probably comes in 9.++mm something size for sporting use and it would be a lot easier to use the russian case with an expanded neck. But so what. this is a project for people that have sufficient time on their hands. The tooling will be a lot more the rifle.

 

[willypete]

Yes, rcmodel, and you're also going to have to know the dimensions of the rims beyond "much bigger than".

Y'know, in case he wants to trim cases or the remove material around the bolt face.

 

[Rem.222]

I don't have my books but I think .356 win would be doable.

 

[Clipper]

My cousin mailed me a .348 case, which I recieved yesterday. Besides the rim removal, I'll have to thin the magazine walls a bit at the base of the case, and in the neck and bullet area, but there's enough material there to make adding stock unnecessary. I should therefor be able to use the whole magazine, though max capacity might wind up being a round down from the 54R...

 

[a98kdoc]

There is a better way to up bore a Mosin-nagant and that's to look at the 9x53 Finn
Same case and a 358 Dia bullet with cases easy to make or bye from Norma.

A

 

[Clipper]

Yeah, but it's not only too easy, it ain't a .348! The whole point is to have a .348, and have the coolest M-N in these parts. Heck, I already have a sporterized M-N, which will handle anything I will ever shoot. I'm doing this strictly because I wanna.