1891 Mauser re-barrel

[lead collector]

Hello everyone,

I have a quick question. I have an 1891 Mauser that was sporterized some years ago. (Not by me)
I like this gun for some reason, and enjoy shooting it, with cast lead. The barrel is worn and while it shoots so so, with cast lead I have been thinking about re barreling it.
The reason is that I have a new take off 3006 barrel that came off of a Thompson compass with the "5R rifling".

I have read that the major thread diameter is .985 and the threads are 12 per inch.
So I am thinking about cutting the new barrel down, and re-threading. Depending on how much I loose off the barrel, we will have to re-cut the chamber. Thinking about cutting it back enough to re-chamber for the 308, because I have hundreds of empty 308 cases around, and not so many 3006's
My gunsmith buddy has both a 308 and a 3006 chamber reamer, so we can re-cut the chamber.

I know the limitations of the 91 action and I just want a lead shooter, that has a good barrel.

What are your thoughts on this project?

[frkelly74]

not sure if the 06 reamer will clean out a previously reamed 308 chamber.

[pworley1]

I would go the 308 route.

[John Taylor]

308 may be a bit hot for that action. 300 Savage may be a better choice.

[copperlake]

I've done that for a '96. Can't remember how much has to be pruned to make it work. The neck is shorter on the 308 and wider at the shoulder and it will clean up. If it's a lead shooter, there will be no problem.

[challenger_i]

While you may be intending to shoot only cast, do consider where the rifle may go after you no longer are shooting it.
As the 308 is a higher-pressure cartridge, someone down the road may feed it Factory ammo and have A Bad Day. Just food for thought...
Other than that, I like your concept.

[TD1886]

Please pick a lower pressure cartridge for that 1891. You might choose an 8x57 Mauser and that's a great cast bullet round.

[Dutchman]

........there will be no problem.

As far as today is concerned you are correct. No problem. But what of the future consequences? In whose hands may not understand all there is to understand? Sure as shootin', some body, some where, at some time is going to put a full power .308 in the chamber and let fly. And because nothing will happen (all at once) he'll do it again and again. Eventually, those consequences will show themselves. To the detriment of him unlucky enough to be holding it when it finally fails.

This is, of course, the diametrical opposite of "no problem" and does not represent the real world eventuality of reality deciding on a resting place somewhere between heaven and h*ll. If you were a statistician you could make an argument for either of the two ends and they would both be correct. This represents the dichotomy of life. No matter what you decide it'll be wrong to somebody.

Dutch

[Larry Gibson]

Consider the 30x57 which is just a shorter chamber done with the 30-06 reamer. That would give you an easily made wild cat with the capacity of the 308W thus avoiding the potential use of 308W ammo in it. The 30x57 maintains the tapered case that the single stack magazine is made for so feeding isn't a problem. Cases are easily formed from 30-06 family of cartridges of from factory 8x57 cases. Reloading dies are simply shortened 30-06 dies. The 30-57 case maintains the '06 length neck also which is best for a variety of cast bullets.

I've rebarreled several M91s to the 30x57 and 35x57 cartridges. They are excellent cast bullet cartridges and also work well with jacketed bullets.

Here you see (left to right0, the 308CBC, the 308W, the 30x57, the 7.65 Argentine and the 30-06.



Cases formed with 30-06 shortened die; 30x57 on left, 35x57 in middle and 30-06 on the right.

[MostlyLeverGuns]

A 300 Savage with a long neck, so 308 cases could be used without trimming would let you use standard dies and your 308 cases. Set the neck at the 2 inch plus 308 length then set-up headspace with a 300 Savage reamer. A 'standard' chamber that avoids the high pressure consequences of factory ammo, and readily available standard dies. Just run the 308's into the 300 Savage sizer and load.

[TD1886]

A 300 Savage with a long neck, so 308 cases could be used without trimming would let you use standard dies and your 308 cases. Set the neck at the 2 inch plus 308 length then set-up headspace with a 300 Savage reamer. A 'standard' chamber that avoids the high pressure consequences of factory ammo, and readily available standard dies. Just run the 308's into the 300 Savage sizer and load.

Down the road in the future someone could shoot factory 300 Savage in and if you think that isn't the equal of the 308 you should check the history about it. It was suppose to be the cartridge for the M14. It pushed, back then, a 150 grain bullet to 2900 fps.

[MostlyLeverGuns]

The max CIP pressure for the 300 Savage is 52,939 psi, the max CIP pressure for the 7.65x53 Mauser is 56,565psi, the max CIP pressure for the 308 Win is 60,191psi. The FACTORY ammunition for 300 Savage is loaded to CIP or SAAMI pressure and less than the CIP pressure of the 7.65x53 Mauser. I am very, very familiar with the 300 Savage, got about 10(?) of them, use them for antelope and deer most every year, sometimes for cow elk. SAAMI pressure is 47000 psi, with modern modern powders it is capable, but loaded to MUCH lower pressures than the 308 and 30-06. Again,The current FACTORY ammunition is loaded to SAAMI standard and IS NOT the same as whatever experiments were done for the 7.62x51(308 WIN) that became the M14. The 7.65 x 53 Mauser and 8x57 actually have the same CIP pressure standard.

[frkelly74]

Consider the 30x57 which is just a shorter chamber done with the 30-06 reamer. That would give you an easily made wild cat with the capacity of the 308W thus avoiding the potential use of 308W ammo in it. The 30x57 maintains the tapered case that the single stack magazine is made for so feeding isn't a problem. Cases are easily formed from 30-06 family of cartridges of from factory 8x57 cases. Reloading dies are simply shortened 30-06 dies. The 30-57 case maintains the '06 length neck also which is best for a variety of cast bullets.

I've rebarreled several M91s to the 30x57 and 35x57 cartridges. They are excellent cast bullet cartridges and also work well with jacketed bullets.

Here you see (left to right0, the 308CBC, the 308W, the 30x57, the 7.65 Argentine and the 30-06.



Cases formed with 30-06 shortened die; 30x57 on left, 35x57 in middle and 30-06 on the right.

That is certainly an elegant solution, if you are a reloader. It solves the problem of anyone shooting factory loads through it. But you are going to have to make your own special ammo. The rifle was designed for a high intensity cartridge in the first place though. Would it necessarily be unsafe with a 30/06 or 308 class cartridge? I suppose that would depend on what kind of treatment it has received in the past century plus.

[copperlake]

As far as today is concerned you are correct. No problem. But what of the future consequences? In whose hands may not understand all there is to understand? Sure as shootin', some body, some where, at some time is going to put a full power .308 in the chamber and let fly. And because nothing will happen (all at once) he'll do it again and again. Eventually, those consequences will show themselves. To the detriment of him unlucky enough to be holding it when it finally fails.

This is, of course, the diametrical opposite of "no problem" and does not represent the real world eventuality of reality deciding on a resting place somewhere between heaven and h*ll. If you were a statistician you could make an argument for either of the two ends and they would both be correct. This represents the dichotomy of life. No matter what you decide it'll be wrong to somebody.

Dutch

All true. Taken to one end, no one would do ANYTHING because.

[405grain]

All of these are fine suggestions, but the only reason that the OP wants to do a caliber conversion is because he has the wrong type of replacement barrel and wants to shoe horn it onto his action. IMHO this is misplaced economy. As much or more effort will be extended into making this barrel work as would be required to just use a better barrel. There's no need to jump through flaming hoops creating wildcat cartridges, or deciding on factory ammunition that matches the actions pressure limitations. Often there's more involved in changing calibers than just the barrel: will the action feed the new caliber? Will the magazine & feed rails need to be altered to accommodate the new caliber? What is the cost in time and money, both in modifying the rifle, and in making the new ammunition (especially if it's a wildcat)?

Here's a novel idea; How about rebarreling that 1891 Mauser with a new barrel in 7.65x53. This is an excellent cartridge that is both powerful and very accurate. The action will feed this cartridge with no modifications. It is well within the pressure requirements that the rifle was designed for. Replacing the barrel will cost about the same as modifying the used 30-06 barrel that was made for some other firearm so that it will fit this action, then chambering it in something that might (or might not) work in this gun. There will be no problems or confusion with ammunition for some later owner of the firearm. 7.65x53 works really good with both cast and jacket ammo, and bullets, cases, molds, and loading information are widely available. Trying to put together a Frankenstein Mauser from wrong parts is just dropping dollars to pick up nickles. If you want a unique rifle in an uncommon caliber, I get that, build it. But if you just want to replace the worn out barrel on your gun to get it shooting again there's no need to go to all the extra steps if you just keep the rifle in it's (already really good) caliber.

[kywoodwrkr]

All of these are fine suggestions, but the only reason that the OP wants to do a caliber conversion is because he has the wrong type of replacement barrel and wants to shoe horn it onto his action. IMHO this is misplaced economy. As much or more effort will be extended into making this barrel work as would be required to just use a better barrel. There's no need to jump through flaming hoops creating wildcat cartridges, or deciding on factory ammunition that matches the actions pressure limitations. Often there's more involved in changing calibers than just the barrel: will the action feed the new caliber? Will the magazine & feed rails need to be altered to accommodate the new caliber? What is the cost in time and money, both in modifying the rifle, and in making the new ammunition (especially if it's a wildcat)?

Here's a novel idea; How about rebarreling that 1891 Mauser with a new barrel in 7.65x53. This is an excellent cartridge that is both powerful and very accurate. The action will feed this cartridge with no modifications. It is well within the pressure requirements that the rifle was designed for. Replacing the barrel will cost about the same as modifying the used 30-06 barrel that was made for some other firearm so that it will fit this action, then chambering it in something that might (or might not) work in this gun. There will be no problems or confusion with ammunition for some later owner of the firearm. 7.65x53 works really good with both cast and jacket ammo, and bullets, cases, molds, and loading information are widely available.

Couldn't agree more.
Change to non-standard barrel/caliber results in dismal resale value.
A real nice original replacement barrel and you will have enhanced the rifle.
YMMV

[Larry Gibson]

That is certainly an elegant solution, if you are a reloader. It solves the problem of anyone shooting factory loads through it. But you are going to have to make your own special ammo. The rifle was designed for a high intensity cartridge in the first place though. Would it necessarily be unsafe with a 30/06 or 308 class cartridge? I suppose that would depend on what kind of treatment it has received in the past century plus.

It is the magazine of the M91 that is the problem. Made of tempered steel with spring like qualities it is not easily modified. The M91s magazine is too short for the 30-06 cartridge. It also is made for the taper of most all Mauser cartridges. The minimal taper of the 308W case [especially if fire formed and just NS'd] at the shoulder can keep the magazine spread apart which can keep the rear of the case from lifting up so the bolt can not pick up that case to feed.

Here is the M91 with a M80 7.62 NATO seated in the mag. Note the bolt will not pick up the rim but will slide over it and will not feed that cartridge.



Here is a 30x57 case seated in the mag. Note the bolt will pickup the rim and feed the cartridge.



One other nice thing about the M91 action with it's straight inline mag is it will feed just about any cast bullet nose profile out there. The round is fed straight up and into the chamber unlike with staggered magazines.

[Larry Gibson]

All of these are fine suggestions, but the only reason that the OP wants to do a caliber conversion is because he has the wrong type of replacement barrel and wants to shoe horn it onto his action. IMHO this is misplaced economy. As much or more effort will be extended into making this barrel work as would be required to just use a better barrel. There's no need to jump through flaming hoops creating wildcat cartridges, or deciding on factory ammunition that matches the actions pressure limitations. Often there's more involved in changing calibers than just the barrel: will the action feed the new caliber? Will the magazine & feed rails need to be altered to accommodate the new caliber? What is the cost in time and money, both in modifying the rifle, and in making the new ammunition (especially if it's a wildcat)?

Here's a novel idea; How about rebarreling that 1891 Mauser with a new barrel in 7.65x53. This is an excellent cartridge that is both powerful and very accurate. The action will feed this cartridge with no modifications. It is well within the pressure requirements that the rifle was designed for. Replacing the barrel will cost about the same as modifying the used 30-06 barrel that was made for some other firearm so that it will fit this action, then chambering it in something that might (or might not) work in this gun. There will be no problems or confusion with ammunition for some later owner of the firearm. 7.65x53 works really good with both cast and jacket ammo, and bullets, cases, molds, and loading information are widely available. Trying to put together a Frankenstein Mauser from wrong parts is just dropping dollars to pick up nickles. If you want a unique rifle in an uncommon caliber, I get that, build it. But if you just want to replace the worn out barrel on your gun to get it shooting again there's no need to go to all the extra steps if you just keep the rifle in it's (already really good) caliber.

Not a "shoe horn solution" at all and resale value if there would be any decrease, is probably a moot point. I'd bet he'd sell the rifle for more, not less with the new barrel. The OP already has a fine barrel, no need to get a new barrel. As much as I like the 7.65 Argentine cartridge (I have 4 Argentine rifles and shoot them all) the cost of a new .31 caliber rifle barrel along with a 7.65 Argentine chamber reamer to rebarrel a M91 action would probably be prohibitive. He could buy a very nice newly made rifle for what that would cost. If doing that, since the rifle already has been "sporterized", recouping such a cost would be very, very unlikely. The OP is going down an excellent path to utilize a fine M91 action.

[lead collector]

Hello everyone,

Its been a busy week end, with a graduation party claiming a lot of my time, so I am just now getting time to read all of your posts.
I believe that I may have opened a can of worms here, with out intending to, but I did get the answer to my questions, and for that I am grateful to you all.
The idea of creating an unsafe gun, that might hurt some one, after I leave the Earth, was the first concern that I had.
So with Larry's 30 x 57 idea, I could all but eliminate that from happening.
The project is still in the consideration stage, and for most of you, it probably looks like a waste of time.
For me, I have my reasons for wanting to play with this, as I like the 91 action, and for what I shoot its perfect. Also I have the gun, and the barrel, and hope to have the time soon.
That said, I have recently purchased a really good south bend lathe, with quick chance gears, and have been working on a few little projects.
I have recently turned down an old 98 Mauser barrel, to the major diameter, and will try to use this to cut the threads and practice on.
This should be a good place to start, with out destroying anything of value. I can borrow a striped down 91 action, to try my sacrificial barrel on before I remove my barrel from my working gun. If all goes well, then I will proceed with the good action and barrel.
I hope to retire in a couple of years, and have some projects that I want to work on, as well as burn a lot of powder, and cast a lot of bullets.
Again, I am grateful to all of you for taking the time to post.

Best regards,

LC

[405grain]

Larry has good advise. I'm biased because I really like the 7.65x53. When you do the build post some photos.