[please be patient while I better arrange the text and post the photos [eventually!]

by Steve Nelson:

This is not going to be a treatise on welding. There are several of you much more qualified than I to write about TIG welding. This is going to describe the trials and tribulations of cutting and welding a standard M98 action to create a short Kurtz action for one of my clients.

Actually I cut and welded four actions before I was through. One will become a 250-3000 for my client and three others will be finished by a friend and amateur gunmaker with more courage than brains!

Believe me when I say that this job is much more time-consuming than I expected. By the time I got to the third and fourth actions, I envisioned that I would be whipping them together like baking cookies ... not so. The clean up is way more trouble than the cutting and welding. Getting those inside bolt raceways dressed up and polished with no visible signs of the welding has proven to be quite a challenge.

But enough preamble. You are all anxious for the meat of the job so here goes.

We chose to use the Turkish M98's for this job because they have large diameter front receiver rings with small barrel threads.This will let us turn down the front diameter to Kurtz size and still maintain sufficient wall thickness. Also they are inexpensive and readily available.

The Mexican Mauser actions would work quite well for this project, of course. However, they are valuable for just what they are and I could not justify destroying the two I have left when the Turkish actions are so much more common. Now all of the Turkish actions I used were manufactured by Oberndorf and have the Oberndorf "M" stamped on the flat just back of the recoil lug and also have the nice Oberndorf pearshaped bolt knob. They do have the very high charger clip guide on the rear receiver bridge. Since we were going to recontour this rear bridge anyway, the clip guide was not a factor. In fact, while I was at it, I went ahead and welded a square block on the rear bridge of two of the actions. This does add a cosmetically pleasing element. One major drawback to the Turkish actions is the large cutout in the top rear of the front receiver ring. This allows clearance for the bullet nose in loading but really needs to be closed up to make a clean looking action. Since it is centered right in the middle of the top locking lug, it is pretty hard to weld it shut without destroying the heat treatment of the lugs. I have chosen to ignore this and have the entire action reheat treated. The Turkish actions seem to be rather soft (even on the lug contact surfaces) so I think they would benefit from this treatment no matter what you’ve doing with them.

Let's start with the action body and then progress to other parts. I set the actions up in the lathe fixture which I normally use for facing off the front of the receiver ring. Using a carbidepart-off tool, I turned a groove in the receiver in front of the rear bridge. Stop before you cut the action completely through either rail. Move the part-off tool an appropriate distance and make the second groove. Aserious word of caution here.

Do NOT try to cut all the way through the action walls in the lathe. Since you are dealing with a heavily interrupted cut, the part-off tool WILL catch and bend the action rails ... guarantee it. Cut the grooves down until there is about 1/8" left and finish the cuts with the hacksaw, by hand or power at your discetion. In this case I was trying to attain a true Kurz guard screw spacing on the finished action so I removed .610" from the action. I wanted a very tight fit of the two halves. In truth you could make the action any length you wanted and, indeed, it could be customized to the exact cartridge length.

Now some details are in order about the fixture I have made to hold the two halves of the actions for welding. I used a piece of mild steel but copper would do even better at absorbing the heat of welding. I just didn't have a piece large enough and didn't want to spend the current price of copper to buy one. After truing up the top of the bar, I centered the part under the mill head, drilled holes for the guard screws to match the original actions, the shortened actions and, while I was at it, the spacing for a magnum action. It is also necessary to mill out for the trigger hanger and the recoil shoulder. I then turned a couple 3/4" lengths of steel rod, sized for a tight slip fit in holes and threaded 1/4-22 for the Mauser guard screw holes. The idea of this fixture is to secure the action halves flat and true to length. I then turned a bar of copper for a slip fit in the bolt ways of the action halves. There is a threaded hole in the copper bar to accept a socket head screw coming up through the bottom of the fixture base to lock the whole assembly together. Naturally, as soon as you finish the initial welds, the actions must be removed from the fixture to expose the inside feed rails for welding.

This is good place for another tip I learned the hard way. When you bevel the sides of the seam preparatory to welding the joint, think about how you are going to have to approach the weld. It is all but impossible to get the nozzle of a TIG torch inside the left bolt raceway. Make your bevels go almost all the way to the inside so you can weld the entire seam from the outside of the action with perhaps just a bit of fill from the bottom feed rails (where the magazine box fits into the action). I did not take this into account on the first action and had a devil of a time cleaning up the gross weld I had to make to close up the seam from the inside of the raceway. I do have an end mill specially ground to match the bolt raceways on the Mauser actions. However, remember the back of the seam is very near the rear bridge and it is difficult to get all the way to the back of that weld seam without hitting the front of that rear bridge.

Now is the time to decide whether or not you want to close up the thumb cut in the left side rail. According John Speed's Oberndorf research, some of the Kurtz actions had the thumb cut and some did not. If you thought about this in advance, you made the original cuts in the receiver to take advantage of the thumb cut and close up most of it with the weld seam. I use my special raceway end mill to machine some mild steel bar stock to match the contour of that raceway and just weld in a piece to close up the cut. You could also use a ball end mill to make a shallow thumb cut ala the Mexican Mauser. Your call. Remember we are making a custom action here so anything goes as long as it is safe.

The photograph following illustrates some of the fixtures I built many years ago for machining and surface grinding actions. The plans came from the fertile fields at Trinidad State Junior College in Colorado. I am sure a call to their offices and a bit of heart-felt pleading would net you a copy. I have seen many other tools for accomplishing this same job. The idea is to machine overlapping facets on the front ring to get it down to small ring dimensions and avoid machining off the recoil lug. On the illustrated action, I first turned down the ring in front of and in back of the recoil lug since I am going for maximum lightness in this little rifle. Then I only had to machine the area above the recoil lug. My usual technique is to hand polish the facets into roundness. My fixture makes the facets at five degree increments so it is fairly easy to clean up. If you used an honest to gosh dividing head, you could get that down to one degree or less.

Now let's look at shortening the bolt. Again I turn to the lathe and that handy ISCAR part-off tool. I suggest making the cut between handle root and the guide rib. That way you can clean up lathe. I cut the first bolt in the guide rib, thinking that would be easier to line up for the weld and would automatically shorten the guide rib at the same time. Well it did both but it required hand filing to clean up the weld and I could have done the whole thing in the lathe in a quarter the time. Ah well, we live and learn ... hopefully.

You will note from the attached photographs that I have machined a sleeve on one end of the bolt and a corresponding pocket on the other. This provides a solid alignment between the two halves of the bolt and reinforces the weld joint. Actually I have read some guides to action modification which recommend silver solder for this joint. Of course that would work fine. If it were carried out down in the extractor collar groove, the joint would be invisible.

Next we need to address the firing pin for this shortened action. At first I thought about cutting and welding it as well. Then it occurred to me that I could simply machine two new grooves at the back to take the cocking piece and cut off the exposed end. Same result but a lot less work. Easy decision. Now some of these firing pins are hard. You may need to use the carbide part-off tool again. There is another issue to deal with now ... see, I told you this job was harder than it seemed.

What about the extractor? Now that we have shortened the bolt, a standard extractor won't fit. Actually this one is fairly simple. Cut off 1/4" from the back of a standard M98 extractor. Turn up a piece of bar stock to an outside diameter of about .750 (to fit the inside curve of the cut extractor) and an inside diameter of .700 (to fit the outside diameter of the bolt body), part off the "tube" you just created to a length of 1/4", and cut out a piece the same width as your extractor. I silver soldered the new shoulder to the old extractor. You could also weld it but my TIG welder decided to lose its brain this morning and wasn't feeding the argon through the nozzle. Oh the joys of modern technology.

The photograph illustrates an original extractor next to the shortened one. Below them is the lathe turned "tube" and the small piece cut out prior to being attached to the new extractor.

The question of trigger guard/magazine box kept me up nights for a while. Ideally I would call up Ted Blackburn and have him make new ones. That is the path my amateur friend has opted to take and, no doubt, much the better approach. For my client I wanted to get this project finished and Ted was not making Mauser bottom metal at the time. Having a few old Argentine 1909 trigger guards around, I chose to modify one of them for this job. Cut through the sidewalls at the back of the box, trim them to length, slide the back wall with the trigger guard attached forward, and weld the two back together. I used the shortened action with the stock inletting screws in place as a guide. The weld seam is a little tricky where it flares at the bottom and the thin sidewalls want to burn through so be careful. This is where a delicate foot control comes in handy. Once the box is welded, you can machine or hand saw and file the back of the floor plate until it fits the new location of the guard bow. Easier said than done, I know, but that pretty much sums up this whole project.One last item is the magazine follower and spring.
Although it is possible to cut a section out of the middle of the original follower and weld the pieces back together as I did ... once ..., you can machine a new one with little more work. Easier still is to substitute spring and follower from a short Ruger M77 or Remington M700 action. The follower spring from the Remington short M700 works fine to fix the often broken springs on the Mini-Mark X actions as well.

I have not even begun to discuss the polishing necessary on this action. Of course that polishing would be necessary on any serious Mauser custom job so it really doesn't come into play when you are figuring the cost/time for this Kurtz Mauser project. In fact there seems to be quite a lot of polishing necessary on most commercial actions. I am certain that many of you have shortened and/or lengthened Mauser actions and probably have much better, more efficient techniques than I have shown here. Please share the wealth. Write to Dave Norin and submit your techniques for the benefit of the fraternity. The best way to learn is to teach someone else how to do something you have done for years.

I dont seem able to copy the photos.

so go to this page; http://www.acgg.org/publications/ and click on " download a sample issue of Gunmaker as a pdf file"

Trax,
I can't get to the photos through the ACGG website either. Is there another way you can post them? I'd really like to see what you're doing.

Me too...

I would be very interested in seeing the photos.

Thanks

This was posted a month or so ago. I was able to both download and print.
Butch

I think it is the same article that was in the ACGG magazine about 3 years ago.
Don

You are right Don. It was the summer of 2008.
Butch

Hey, I've just come across your post and i know that in Gunsmithing by Roy Dunlap he shows the process of shortening a Mauser action.

If you want a detailed article with good photos of each step get ' The Gun Digest Book of Riflesmithing' by Jack Mitchell. It has a complete section devoted to shortening of a Model 70 action ,but the process is the same for a Mauser. Gunsmith in this case was Joe Reid,a friend who has since retired. All the welding is Oxy-Acetylene torch. Joe was absolutely the best welder I have ever seen and I've seen a bunch. The book is an excellant book on basic riflesmithing and well illustrated by the operations being performed by Joe Reid and Sterling Davenport another fine Tucson gunsmith. It was published around 1982 but you can still occaisonally find a copy.

Zimbabwe,
I have that magazine and article. I have read it several times.
Butch

quote:

Originally posted by zimbabwe:
Gunsmith in this case was Joe Reid,a friend who has since retired. All the welding is Oxy-Acetylene torch.

I just want to point out that this is incorrect. I have seen others claim the same thing, and I would guess that they got that impression from the photos that accompanied the article.

Mr. Reid Tig welded the action together. He only used OA to fill in the "Winchester" lettering on the left action side-wall. (BTW, I have never understood why he didn't tig weld to fill the letters....)


On a different note, do you know if Joe had a son who ran a gunshop here in California? In Healdsburg CA there was a gunshop in the early 90's called Joe Reid's Guns. I have always wondered if there was a connection.

Joe did a lot of work for me before he retired here in tucson and to the best of my knowledge the shop did not have Tig equipment. I could be quite wrong of course.

Start with two actions, cut in different locations, swap & weld, then you end up with one short and one long...

quote:

Originally posted by montea6b:
Start with two actions, cut in different locations, swap & weld, then you end up with one short and one long...

You make it sound soooo easy.

Roy Dunlap used oxyacetylne to weld his shortened actions. I think he used OA for all his gun work.

One thing I would like to point out is that you see very few people doing this work. I am not talking so much about the professional gunmakers, but rather about the very talented folks that post here on AR that do a lot of their own work for theirselves or for a few others.

I am going to postulate that one of the main reasons for it is that nobody wants to be responsible for the cost of the ruined action in the event the action does get ruined!

As usual I'm probably a majority of one but to me it has always been something I didn't understand. I well understand the reason for lengthing an action for some of the long magnum rounds but except for the fact they look neat I never really understood the need for a short action. I had friends who built them in Gunsmith school and they were never able to give me any real reason other than want. You can easily block the magazine on a shorter round and if you just want the shorter stroke you can probably even move the bolt stop and extend the ejector far easier than shortening an action. But that's what makes a custom rifle --- someones want. Ther's probably really no explaining it as we all are guilty of it.