View Full Version : VZ 24 mauser 458 win mag conversion?

April 21, 2011, 02:20 AM
was looking at midwayusa last night and saw a 458 win mag barrel for a 98 mauser for i think 229.99. if i installed this barrel in my rifle what other parts would need to be upgraded? for example will my stock bolt work? what about magazine length? BTW this would be my first sporter attempt i guess u could say. would also appreciate what u think the end total cost would be. As always thank you.

F. Guffey
April 21, 2011, 04:51 AM
I do not use gages as in head space type, others rent and or purchase a head space gage. New, the cost of a reamer could be $140.00 + or -. The magnum uses a different bolt face and the bolt handle will need to be turned down for a scope and then there is the stock the barrel channel will require a lot of work unless the stock is replaced and then there is the feeding meaning a lot of work is required to get the large case to feed.

And then there are tools, lots of tools, some will make you wish you had never started the project like the barrel vise with the cute little blocks of wood, to buy time the manufacturer of the barrel vise will instruct you to find rosin for extra grip, I will tell you the little blocks of wood will burst into flames from heat before the barrel comes off of some Mausers and Eddystones (M1917).

The barrel will not be finished meaning it is not blued, I would suggest you start with an easier project as in going from 8mm57 to 30/06 or 270.

I am starting on another 2 builds, I make no claim to the bench 'rester' world, so this one will be more like a rifle in the crack shot world, My wife called the range and ask Dotty if she would give me a message, Dotty ask her if I was the good looking one, my wife answered with "No, he is the one that looks like he is handy" and Dotty said "We got one out here that looks like a plumber" and my wife said "That's him"

Anyhow, I have $25.00 each in the barrels plus shipping and $50 each in the rifles then there will be hours and hours of work with thousands of dollars worth of tools, and a friend said "Drop them off and I will do them for you".

F. Guffey

April 21, 2011, 07:13 AM
Alternatively, look at E R Shaw's pricelist (http://www.ershawbarrels.com/scb-price-list.php). For roughly $400 you get a barrel professionally installed into your receiver and tested, and you can spend all your time on doing all the other adjustments described by FG. But you won't have to worry that you made an error in headspacing, and you won't need to rent all the tools for barrel installation.

April 21, 2011, 12:35 PM
Biggest problem with turning any milsurp into a magnum is reworking the feed rails. If done properly, they can be a dream. If done wrong, it can quickly become a nightmare. I have reworked several milsurps that had a botched job on the feed rails. It is a lot of work. For your first milsurp conversion, I would recommend a standard bolt face cartridge for the project. There are enough other things to learn to do right.

April 21, 2011, 10:22 PM
+10 on starting this adventure a little simpler. You will definitely want to buy a copy of Jerry Kuhnhausen's Mauser shop manual before you spend a dime on parts ... that will give you a really good idea of what you might be getting into. I've done many of these (ranging from 45acp to .330 Dakota) ... and I would recommend doing one that has the fewest complications for your first one ...

If you are interested in a 458, then maybe consider a 35 Whelan ... it should feed well and use a standard bolt face ... so two major complications are gone by choice. The 35 Whelan isn't a 458 win mag, but nothing in the lower 48 is likely to notice the difference ;)

You didn't mention what kind of machine tools you have access to ... a lathe and a mill are nice, but not necessary if you barrel is threaded correctly and short chambered.

Once again, read, read, read ... and then read a little more ... and THEN make a list of what you will need and THEN start to buy parts. This can be a lot of fun, but it won't be fun at all if you only get 85% done.

Be safe,


April 22, 2011, 05:17 AM
The feed rails are easy with Walsh's instructions/drawing.
I would have never figured that out.

The bolt face is not easy. It is an interrupted cut on hardened steel.

The extractor mod is easy.

Lengthening the magazine is medium difficulty with a mill. Easier to buy PAWS bottom metal.

I do not think anyone's first Mauser sporterizing should be a magnum conversion.

April 22, 2011, 11:22 AM
First of all thanks everyone for your responses. Now the reason i would doing this conversion is to have an affordable big game cartridge rifle. although i dont plan on going to africa in the near future. i do have access to a mill but thats about it unless i can use car tools which i doubt have any use.

April 22, 2011, 11:32 AM
If by "big game" you mean African top-5, then maybe the 35 Whelan wouldn't do it for you, but if you mean North American Big game, then you might want to read a little about that cartridge. My first Mauser build was a 300 Win Mag ... and it turned out well, but I really did feel like I would have been a lot happier if I had started off with something a little less complicated. I've never done a 458WM, so I don't know if the reduced bottle-neck makes it harder to get to feed smoothly or not ... it certainly doesn't look like it would make it easier :eek:


April 26, 2011, 11:34 AM
Unless you are a qualified gunsmith this is not a DIY job. While headspacing "could" be done in a hobby shop if you knew how AND had the proper tools, you need to open the bolt face to accept a magnum case head and you will need to modify the bolt raceway so that the fat rounds will feed. It would be pure punishment to modify and use a military stock on such a rifle, get something with good design and a nice recoil pad.

May 22, 2011, 12:52 AM
Unless you want to buy lots of tools and spend about 200 hours using them, I think a Ruger No. 1 in .458 Magnum is a very good deal.

James K
May 22, 2011, 04:14 PM
The Shaw site says "alter actions to standard Magnum calibers - $65". That is in addition to the barrel and installation, but IMHO, if they will do all the action work involved for that small amount of money, let them do it. I know I couldn't have done it for that.