View Full Version : boltface on Mauser actions

October 9, 2009, 07:30 PM
I'm a big fan of old German cartridges, and, having trouble finding guns in those calibers I'm considering custom guns. How much does changing to bolt face from a standard .470 to .510 or so add to the cost of building?

James K
October 9, 2009, 08:02 PM
Maybe others will provide better info, but I think the bolt face and extractor alteration will be the least of your problems. Getting cartridges like the 11x60R Mauser or the 9.5mm Turkish to feed through a Model 98 magazine would be interesting, not to mention finding a barrel of the proper bore and groove diameters for whatever round you choose.

One thought is to find a Siamese Mauser (Japanese made) that already has a large bolt face and maybe a magazine that won't need too much work. They are often reworked for .45-70, so should be a possibility for other cartridges of that era.


October 9, 2009, 08:24 PM
My first target is a 9.3x64 brenneke, it was made for a standard Mauser action. Biggest issue so far is finding someone with the right reamer and head gauge.

October 10, 2009, 01:56 AM
Opening the bolt face is pretty straightforward for someone who has a lathe and a mill and knows how to use them. Many smiths charge about $50-$75 to open a bolt face.

October 10, 2009, 02:15 AM
Here is something you might consider.The military mausers are originally for a 57mm case length.You are looking at a 64mm case length.I'm not saying it can't be done,but its a lot of work.The mag box is just short.Darn.
Now,if a P-14 enfield action was gathering dust somewhere,the 303 Brit rimsize is about right,and the p-14 can handle a .375H=H for length,but,gosh its a lot of work and the P-14 rifle has a lot of value .

You might try looking at a Brownell's catalogue at the CZ action .Its under $600 and trust me,custom gunsmithing a milsurp won't be more economical.

And,you might look at the Montana Rifleman M-70 clone.He makes barrels,too.He can sell you a barreled action for around a grand in what you want,I think.

October 10, 2009, 07:59 AM
The P14/17 action is something I'm looking for for a 8x68S :)
Thanks for the price info, looks like it's not going to be a serious part in the overall scheme.

Harry Bonar
October 10, 2009, 11:39 AM
You need the bolt face opened up to around .500 - not much. The 9.3X64 works great through the 98 action - I've built several of them with minor rail alteration and extractor. It's a SUPER ROUND - ballistically equal to the 375H&H. Recoil is very nice! The 9.3X62 also works well in unaltered 98 actions - most of mine, including a 416 Taylor are built on Turkish 38 actions!
These cartridges show that you are very savy! They are some of the best, if not the very best, all round cartridges! Small deer to Cape Buff - great penetration and little meat damage - they are gaining in popularity!
Harry B.

October 11, 2009, 08:55 AM
I opened a VZ24 to 300 Win Mag 4 years ago.
Over the last 4 weeks, I have converted (2) 1908 Braz Mausers and (1) VZ24 to 7mmMag.

The lathe bit should be carbide.
The end mill should be carbide.
The sides of the bolt face hood need to be widened at the bottom.

You also need to grind on the extractor, mill out the magazine length or find a longer trigger guard, cut the length of the feed ramp, and cut the width of the feed lips.

October 11, 2009, 09:55 AM
Thanks for the pictures, now I can show the guys in my shop what to do. I presume the mill step is to polish the face after sizing it on the lathe?

October 11, 2009, 10:20 AM
I believe he is simply widening the cut for the positive feed up into the bolt face. The lathe can't do that part.

October 11, 2009, 06:11 PM
I was doing that, and cleaning up in the corners.
The carbide lathe tool I used has a radius on the tip, but the end mill I used makes a square cut.

To get the rifle to feed, I use dummy cartridges and see where it holds up.
a) I once made round nosed dummies, and then went hunting with pointy triple shocks, only to find out I was hunting single shot. The jump from magazine to feed ramp is easy to get hung up for a pointy bullet.
b) My dummies were feeding, but getting beat up. The bolt face shroud needs to be bigger at the bottom. I flared the opening at the bottom of the bolt face, and dummies stopped getting beat up.

I think you are supposed to mill out .040" in the rear of the magazine and .020" in the front.
The feed ramp does not need any more cutting on the ramp part, just how far back it goes. That is a vertical cut, but angled, like the ramp.

October 11, 2009, 06:34 PM
It is true,many mausers have been stup for longer cartridges.I stand corrected.

A setup I have used successfully on boltfaces ,I have an angle plate with a vee-block on one face.I set it in the vise on a Bridgeport,and put the bolt in it.I center up with an indicator,then use a small boring head with a carbide boring bar,just a small stoned corner break for a radius.
I use magic marker to get my touch-off,with the mill in neutral.Then I just dial .001 or so,whatever works,on the boring head,and turn the spindle by hand,scraping out the diameter.Then,I can come back with a1/2 in end mill and just barely skin the bolt face,and then offset the .017 or so to clean the sides

All one setup.

James K
October 11, 2009, 08:48 PM
Hi, Mapsjanhere,

I guess I assumed that you had all the other stuff worked out and were only inquiring about the bolt face. As indicated, converting a rifle to a whole different and larger/longer caliber is not an easy task. The length itself is not too big a problem (tens of thousands of Mausers were converted to .30-06 (7.62x63) and generally worked OK. But modifying feed rails can be tricky and more than one gunsmith has ruined an action getting it right. Things are simplified if you are willing to go with a single shot, just to test the old ammo.


October 11, 2009, 09:23 PM
Well, I'm starting with a new action. The tricky part of making it fit is something I have to work out. The good news is that I employ some very capable machinists who know how to run a mill and lathe, and the information in this thread just told me what I need to tell them to help the project along. If I could figure out how to do the head spacing I could probably get the whole thing done in house by getting a reamer from PTG.

October 11, 2009, 09:57 PM
It seems like there is a book titled something like Rebarreling and Chambering rifles.Try Midway.It will tell you how.

October 11, 2009, 11:46 PM
This is just my opinion, and it is somewhat autobiographical: You will learn a LOT by doing the whole thing in house. You can get a book called the "Mauser Shop Manual" or some such thing ... it was written by Jerry Kuhnhausen ... if you google it you will find it readily available online. I can't remember which of the guys here recommended it to me, but that was many custom mausers ago. Head spacing is well within the reach of someone who has some mechanical aptitude (a lathe doesn't hurt, but isn't really necessary if your barrel is already short chambered), patience and respect for the job (willingness to go slow and do it right). I haven't done a 9.3, but I did a 300WM and it sounds like that had all the hassle of the 9.3 in terms of bolt-face, rails, etc.

Good luck ... and you definitely found the right place to ask questions!! A better group of willing hands you will not find.


November 1, 2009, 12:49 PM
I have Jerry Kuhnhausen's Mauser book and Walsh's book on Mausers, and Walsh is better for me.

Unless I miss my guess, Jerry taught a course, and had fixtures to look at. The lecture notes were all prose and not organized. He turned it over to Heritage gun books that forgot to edit it and just printed from the jumble of papers handed to them.

The feed lips mod and the fixtures in Walsh are per drawings with dimensions.
Jerry Kuhnhausen has written many books, but Walsh has written only one book. Sometimes I think that Walsh may have written his book in reaction to how badly Jerry Kuhnhausen's Mauser book was written.