.458 on '98 Mauser?

Kurt Learning · Aug 2, 2019

Is it possible to build a .458 Winchester Magnum on a 1898 Mauser action?
I have a NOS Columbian receiver to start with. R. Famage, 1957.
I'll have to open the bolt face and stretch the magazine.
Any insights are appreciated, thanks in advance.

johnoder · Aug 2, 2019

Case length of 2.5" is .250" longer than 8 X 57 and .270" longer than 7 X 57. Might be doable if you don't expect to clear long projectiles hanging out of case

thermite · Aug 2, 2019

Kurt Learning said:
Is it possible to build a .458 Winchester Magnum on a 1898 Mauser action?
I have a NOS Columbian receiver to start with. R. Famage, 1957.
I'll have to open the bolt face and stretch the magazine.
Any insights are appreciated, thanks in advance.

View attachment 262406

Just use the longer commercial, not Military, Magnum Mauser "large ring" action.
That's what they made them for.

And still do:

Magnum - www.mauser-rifle.com

Most of us would just use a more appropriate cartridge to make best use of what you have. The one it is presently chambered for at the head of the list.

Why try - and probably fail - at creating a useless "blivet" [1] out of a right-decent firearm?

[1]Five pounds of s**t stuffed into a one-pound bag. Yes. The overflow is messy.

Kurt Learning · Aug 3, 2019

Thanks for the input. This is why I am here. (Really, I have no where else to go with some of my questions.)
But if it is a question of trying to put too much into a small space, I would say this action was made for it.
The Columbian Famage receiver was made for a .30-'06.
Admittedly, it is a standard '98 action, designed for a 57mm case length cartridge, that has been modified to take a 63mm cartridge, by cutting a notch in the receiver ring to allow for a longer cartridge.
But if the receiver can take a .30-'06, why can't it take the .458? The maximum cartridge length is the same.
Does anyone have experience with this conversion?

MilGunsmith · Aug 3, 2019

Yes it can be made. Many have been done in the past. The .458 was designed to fit in a 30-06 length action. Parker Hale made many factory guns in that caliber and action. I have one that was done in .375H&H.

Kurt Learning · Aug 3, 2019

It would appear as though my next step would be to open up the cartridge bearing surfaces inside the receiver.
If anyone can supply dimensions, articles or information, I would be most appreciative.
Thanks

tobnpr · Aug 4, 2019

Kuhnhausen recommends no longer than .30-06 OAL cartridge conversions for military M98 actions.
Anything longer requires removal of metal from the feed ramp area- which is behind the lug and would weaken this area.

Kurt Learning · Aug 4, 2019

tobnpr said:
Kuhnhausen recommends no longer than .30-06 OAL cartridge conversions for military M98 actions.
Anything longer requires removal of metal from the feed ramp area- which is behind the lug and would weaken this area.

My source indicates that max OAL is the same for the two cartridges.
See diagram posted.

Rob F. · Aug 4, 2019

tobnpr said:
Kuhnhausen recommends no longer than .30-06 OAL cartridge conversions for military M98 actions.
Anything longer requires removal of metal from the feed ramp area- which is behind the lug and would weaken this area.

Kurt Learning said:
My source indicates that max OAL is the same for the two cartridges.
See diagram posted.

I read what he said as you are fine at 30-06 length but do not go longer, since you are at the max length and not longer then you are OK
What would be longer?

75sv1 · Aug 5, 2019

If you are looking for info on opening the feed rails, then Duane Weibe has a booklet on how to.

Kurt Learning · Aug 5, 2019

Thank you Sir.
That looks like the very information I need.
(At least for now. Experience tells me other questions will follow.)

75sv1 · Aug 7, 2019

I looked an my Columbian action and another standard length action. The feed throat was 3-5/8 on the Columbian vs 3-1/5 on the other action. I used a tape measure though. My digital caliper was acting funny. I do not have the bottom metal for the Columbian. I did measure some Browning/FN 90% receivers I have. They were shorter still. I did not get to measure on FN rifle I have. The ejection port, receiver ring were the same on both. My problem with putting a .458 Win. on the Columbian is the notch in the top receiver ring. Compare PSI ratings vs a 30-06. I did not look them up though.

Kurt Learning · Aug 7, 2019

I took a look at the SAAMI standards page, to compare pressures.
They prefer to use copper “crusher” units of pressure rather than PSI.

While the .458 is about 6% higher than the .30-'06, this may be due to the fact that the .30-06 is a much older cartridge.
The .458 has the same pressure as a .25-'06, and only 2% higher than the commonly used .223, .243, .270, .308, .35 Whelen and .358 Winchester.
It is also 2% lower than the .264, .284 and .300 Win Mags.
All of which have been used successfully in '98 Mauser actions.

As for the magazine, I will probably “stretch” a commercial steel magazine.

https://saami.org/wp-content/uploads/2019/02/ANSI-SAAMI-Z299.4-CFR-Approved-2015-12-14-Posting-Copy.pdf

mechanist · Aug 8, 2019

Bolt thrust is more important than pressure. The pressure that a given cartridge generates, multiplied by the surface area at the rear inside surface of the casing is the amount of force that will be acting upon the action. As you can see, a low pressure cartridge that has a large case head can actually exert more force against the bolt and receiver than a high pressure cartridge that is smaller in diameter. If the pressure of a 458 mag is 6% higher than a 30-06, and the 458 has a larger surface area, then it is delivering significantly more bolt thrust.
Another consideration that you should think about before committing to this caliber, in this action, is feeding. The 458 mag is decidedly a dangerous game caliber. It's not simply a matter of if the cartridge will fit, but will it feed smoothly and reliably? This can be done, and it has been done, but it requires a lot of patience and a steep learning curve to develop the skills that are needed to optimize a standard 98 action for a cartridge that deviates so much from the dimensions of the round that the receiver was designed for.
I don't mean to discourage you in the least. This project is very ambitious, and can turn out to be very rewarding. There's great pleasure in building your own custom rifle on your own terms. I would only advise that when using something as a learning tool, first do the learning on something that doesn't matter as much. As an option you could pick up an inexpensive 1893 complete action from Sarco and use that as a practice mule. In gunsmithing schools they always have you learn the tricks of the trade on a junker receiver before moving up to do a classic build. If you make a mistake opening up the feed rails on a well used 93 there are far fewer tears than with a 98. Even if you just build a "truck gun" on a small ring action, it will teach you all kinds of things like stock work, scope rail mounting, hand fitting parts, chambering and installing a barrel, and finishing the metal. My suggestion is: practice first, then jump in the deep end.

9finger · Aug 8, 2019

mechanist said:
Bolt thrust is more important than pressure. The pressure that a given cartridge generates, multiplied by the surface area at the rear inside surface of the casing is the amount of force that will be acting upon the action. As you can see, a low pressure cartridge that has a large case head can actually exert more force against the bolt and receiver than a high pressure cartridge that is smaller in diameter. If the pressure of a 458 mag is 6% higher than a 30-06, and the 458 has a larger surface area, then it is delivering significantly more bolt thrust.
Another consideration that you should think about before committing to this caliber, in this action, is feeding. The 458 mag is decidedly a dangerous game caliber. It's not simply a matter of if the cartridge will fit, but will it feed smoothly and reliably? This can be done, and it has been done, but it requires a lot of patience and a steep learning curve to develop the skills that are needed to optimize a standard 98 action for a cartridge that deviates so much from the dimensions of the round that the receiver was designed for.
I don't mean to discourage you in the least. This project is very ambitious, and can turn out to be very rewarding. There's great pleasure in building your own custom rifle on your own terms. I would only advise that when using something as a learning tool, first do the learning on something that doesn't matter as much. As an option you could pick up an inexpensive 1893 complete action from Sarco and use that as a practice mule. In gunsmithing schools they always have you learn the tricks of the trade on a junker receiver before moving up to do a classic build. If you make a mistake opening up the feed rails on a well used 93 there are far fewer tears than with a 98. Even if you just build a "truck gun" on a small ring action, it will teach you all kinds of things like stock work, scope rail mounting, hand fitting parts, chambering and installing a barrel, and finishing the metal. My suggestion is: practice first, then jump in the deep end.

Let's add to that duration. Slower burning powders pushing heavier projectiles exert that force over a larger area, as you accurately mentioned, for a longer period of time.

Kurt Learning · Aug 9, 2019

Mechanist, I appreciate the delicate way in which you warn me of the difficulties and offer reasonable alternatives and paths for learning.
However I have been building custom Mausers for 20 years, both on the '96 and '98 actions. I already have a mock up using a junker '98 to cut and weld until I get the feed rail dimensions worked out. My first choice for a bolt will be a commercial FN. All shooting will be done with reloads, and I only need to exceed my neighbor's .45-70. We're buddies and a little competitive. Also, I have 45 years experience as a gunsmith, worked as a machinist, and have a degree in Mechanical engineering. But I believe when embarking on a new project, it is wise to ask the opinions of others that may have more experience. My check has already been mailed to Duane Weibe. Bit by bit, we'll get 'er done. Thank you for your considerate response.

Kurt Learning · Aug 9, 2019

Thank you Thermite.
For failing to address my questions, not offering any real assistance and using this post to air your social views.
Please go back and continue your rants on gun control.

Butch Lambert · Aug 9, 2019

My 458 Lott on a VZ24

Dennis Olson did the metal work.

mechanist · Aug 9, 2019

Kurt: Excellent! I'm glad to hear that you have the experience and background for a project like this. On a lot of forums we all see guys that are new to building, and sometimes bite off more than they can chew for their beginning project. Way too many people will try to discourage folks like that, telling them that it's too hard or they don't have the talent or tools, etc. Worst of all are the ones that say "Just buy a 'Remchester', it'll cost a lot less than trying to build something yourself." Those guys just don't get it. When someone says that they want to do build a rifle, either sporterizing a milsurp or doing a scratch build, the best course is to offer support and advise.
I'm a mechanical engineer and have been building sporting rifles on large and small ring actions for at least a dozen years. It's a very rewarding hobby. Here's a thought: Though the 98 action is a very good platform for a magnum caliber rifle, have you given any thought to the Pattern 1914 Enfield action? It's already got a "magnum" bolt face, can accept longer cartridges than a Mauser, and is more than strong enough for a magnum action. (but it takes a little more work to be as pretty as a Mauser)

Kurt Learning · Aug 9, 2019

That is a truly beautiful rifle. And I see that it is based on the Czech VZ-24 military rifle with thumb-cut for clip loading, a notch at the rear of the forward receiver ring for longer cartridges, and a Argentine style hinged floorplate.
Did you do the stock work?
And I tip my hat to your photography skills.
I'm currently working on a VZ-24 with a heavy barrel in .308 and a laminated target stock.
Thanks for sharing.

.458 on '98 Mauser?

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