7x57 DWM to 375hh

[Dsprech3]

I have a pre ww2 Mauser 7x57 DWM Brazilian contract barreled action that I want to convert to a 375HH to make a type of “Mauser 98”. Has anyone done this? And what type of alterations would need to be done to the magazine and other things to accommodate that new cartridge?
Thanks!

 

[mdwest]

It can be done… but it’s a big task..

A typical magnum conversion for something like a 458 win mag or 416 Taylor (shorter than a 375 HH) requires the magazine to be tweaked a bit, the bolt face opened up, feed rails opened up, etc…

When you step into the longer magnums like 375 HH you’re also looking at a good bit of machining being done to both the front and rear of the action and having the magazine box opened up/extended as well..

 

[AZDAVE]

It can be done.. However needs a GOOD gunsmith to do the work.

You will need to either buy an aftermarket bottom metal with the correct length and mag follower. or modify the current box in length and width, replace the follower for one designed for 375.
The action will need to have some metal removed from the rear of the action and a small amount from the front. The bolt stop and ejector will have to be modified to allow the bolt to come father to the rear.
The feed rails will need to be opened up properly to get it to feed the soft's and solids you plan on using. and rebarreled to 375 H&H. and bolt face opened up.

You will most likely save $$$ just buying a M70 win or look for a used CZ, Whitworth, ruger ETC.

 

[F. Vaccaro]

With the amount of work needed with this conversion, I’d look seriously at the 9.3X62, & I’m a big fan of the .375 H&H Mag.

 

[mdwest]

FWIW, my 416 Taylor is built on a DWM Brazilian action. It is a truly wonderful DG rifle.. If you are absolutely committed to converting your standard length mauser action to a DG caliber, I'd recommend you look hard at the 416 Taylor option..

ER Shaw can make you a 416 Taylor barrel affordably.. and shaw also has a "magnum conversion" that is affordable where they will do all the necessary work on the action to have it feed and extract/eject the 416 Taylor well/reliably..

The recoil difference between my 416 Taylor and my Win 70 375 H&H is barely noticeable.. if you can handle the 375, you should be able to handle the 416 no problem..

and while the 375 will certainly drop anything on 4 legs anywhere on the planet, a 400gr A-Frame from the 416 will do it with significantly more authority..

It'll cost you 1/2 as much to go 416 Taylor as it will to go 375 H&H.. and your probability of success is much greater with the 416 Taylor (as @AZDAVE mentioned, youre going to need a very good smith.. and you are going to pay for several hours of shop time to get a 375 H&H to work)..


Or.. if you absolutely must go 375... consider 375 Ruger instead of 375 H&H.. 375 Ruger will fit in the standard mauser action easily.. and will give you the same ballistic performance as the H&H..

 

[Dsprech3]

FWIW, my 416 Taylor is built on a DWM Brazilian action. It is a truly wonderful DG rifle.. If you are absolutely committed to converting your standard length mauser action to a DG caliber, I'd recommend you look hard at the 416 Taylor option..

ER Shaw can make you a 416 Taylor barrel affordably.. and shaw also has a "magnum conversion" that is affordable where they will do all the necessary work on the action to have it feed and extract/eject the 416 Taylor well/reliably..

The recoil difference between my 416 Taylor and my Win 70 375 H&H is barely noticeable.. if you can handle the 375, you should be able to handle the 416 no problem..

and while the 375 will certainly drop anything on 4 legs anywhere on the planet, a 400gr A-Frame from the 416 will do it with significantly more authority..

It'll cost you 1/2 as much to go 416 Taylor as it will to go 375 H&H.. and your probability of success is much greater with the 416 Taylor (as @AZDAVE mentioned, youre going to need a very good smith.. and you are going to pay for several hours of shop time to get a 375 H&H to work)..


Or.. if you absolutely must go 375... consider 375 Ruger instead of 375 H&H.. 375 Ruger will fit in the standard mauser action easily.. and will give you the same ballistic performance as the H&H..

All great info! Thanks fellas, I appreciate it. I’m not really determined to stick with the 375 but just want to make sure I have a cartridge that most African countries would allow for any type of game.

 

[mdwest]

I should have mentioned.. If youre not a reloader, the 416 Taylor option might not be for you.. there are very few factory ammo options out there for it... If you are a reloader, all of the components are pretty easy to come by.. the same projectiles used for 416 Rigby, 416 Rem Mag, etc are used in the taylor... common powders like 4064, Varget, etc work well in the taylor, and there are a few companies that make properly headstamped taylor brass (you can also resize 338 WM or 458 WM brass to 416 Taylor)... but factory ammo options are extremely limited..

If you arent a reloader, there are enough 375 Ruger and 416 Ruger factory ammo options available to keep you in all the DG hunting you ever want to do...

 

[Dsprech3]

I haven’t looked in my reloading book at those cartridges yet or how available especially the Taylor is. I have a single stage I reload my 308 and a couple others with. I have seen 375’s out there but reloading it could bring it down a few cents hah.

 

[mdwest]

Single stage is all I use.. any decent one (RCBS, Lyman, Hornady, etc) will load either 375 H&H or 416 Taylor with no problem (I actually just loaded a hundred rounds of 375 HH last week and have about 125 pieces of brass primed up for the taylor that I'll load next week)...

While bullets for both of them are expensive, and they are both powder hogs compared to a 308... hand loading for them is MUCH more affordable than factory ammo for certain...

 

[sierraone]

@Dsprech3, You didn't ask for my opinion, but here goes anyway. Pay attention to what @mdwest and @AZDAVE tell you. OR simplify your interest and go buy a M 70 .375 H&H, attach a 1x5 scope on top and go kill anything in Africa with the possible exception of an elephant. You can buy 4-5 different size factory bullets/ammo if you don't reload. Much fewer headaches and costs. Happy Hunting.

 

[cash_tx]

Food for thought: earlier this week i held a new Winchester Model 70 Safari Express in 375 H&H (FN build from Portugal), and it looked to be very well put together. For $1,600 I think it makes more sense to go that route than trying to make a round hole into a square. I'm a huge fan of 7x57 and would be inclined to leave your barreled action as is, and just go buy the Model 70 Safari Express. Or you could always look around for a used Whitworth Express in 375 for around $1,000-1,200.

 

[IvW]

I would not, rather buy a 375 built on a magnum action.....sorted

 

[Dsprech3]

Yea it seems to be too much work to be done on the metals and too much material taken away to make a magnum where that seems like it could have the slight possibility to be a bad day maker. I may just well make it a sweet little 7x57 and look for another 70 or 98. Just love the Mauser actions but it’s not like this is the last one out there. Can’t ever have too many guns anyway.

 

[cash_tx]

You can never have too many M98-based 7x57's; but i have three of them, so I'm a bit biased. ;-)

 

[Hunter-Habib]

Too much metal would have to be removed in order to accommodate the large .375 Holland & Holland Magnum cartridge. I also discourage this practice.

 

[Dsprech3]

Too much metal would have to be removed in order to accommodate the large .375 Holland & Holland Magnum cartridge. I also discourage this practice.

Yep. Keeping it like it is in 7x57. Although, I did happen to get the tiger grain stock i mentioned in another post and I was able to get a 100 year old brand spanking new barrel. Never fired, never set in an action. Had the original cosmolene in the barrel.

 

[Hunter-Habib]

Yep. Keeping it like it is in 7x57. Although, I did happen to get the tiger grain stock i mentioned in another post and I was able to get a 100 year old brand spanking new barrel. Never fired, never set in an action. Had the original cosmolene in the barrel.

Very Sensible. I could write an entire book about my adventures with JUST my 7x57mm Mauser (a Churchill Gunmakers Model Deluxe) over the years ever since 1989.

 

[Dsprech3]

Very Sensible. I could write an entire book about my adventures with JUST my 7x57mm Mauser (a Churchill Gunmakers Model Deluxe) over the years ever since 1989.

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That’s awesome man! Thanks for sharing!