Part 2: building a switch-barrel Mauser: in Part 1 (10/10 issue) Coffield removed the barrel and lapped the action. Now he uses a special tool to remove the charger guide, then reshapes the tang and stock wrist.
One of the most unusual and desirable collectables is a Mauser takedown sporter. with a takedown rifle, the barrel can be removed from the receiver by the user. The idea behind this was to make it easier to transport the rifle. Needless to say, takedown Mausers are darn rare. In. fact, I could make the case that you're much more likely to run across a set of dentures for a chicken than you are to encounter one of these rare Mausers.
As a kid I had seen a number of takedown rifles produced. by Winchester, Savage, and a few other makers; and I was impressed. I always wanted one but I could never seem to put together the necessary funds when one was available. That was true back when I was a teenager and it's still true today!
Because of this, I decided just to build my own takedown rifle. In fact, I decided to make my rifle a little different and to make it with two barrels in two different calibers. It would not be just a takedown rifle; it would be a switch-barrel rifle!
I decided to Use a standard 98 military Mauser action because it's still relatively inexpensive, quite strong, and lends itself to this type of project. The calibers I choose were .30-'06 and .22-250. Theoretically I would be able to hunt virtually any type of normal game animal with this one rifle.
In Part 1 of this series I began with a VZ-24 7mm Mauser I obtained from Century ArmS International, Inc., 430 South Congress Ave., Suite 1,. Dept. SGN, Delray Beach, Fla. 33445, telephone 1-800-527-1252. This was a very well used military rifle that probably came from Central or South America.
It showed signs of extensive use and very little maintenance. The bore of the barrel looked to be as pitted and rough as the inside of an old iron sewer pipe. This was definitely not a rifle any self-respecting collector would ever want. However, for our purposes, it was ideal. If you need a Mauser action for a project like this, check with the folks at Century. More than likely, they can fix you up.
While I enjoy modifying old military rifles, I do want to urge anyone undertaking a project like this to use only rifles that have little or no interest or value to collectors. Let's face it; there's a constantly diminishing pool of collectable grade older military firearms.
As responsible gun owners, gunsmiths, and collectors, we owe it to the next generations to preserve as many of these historic artifacts as practical. Besides, there are still thousands and thousands of beat up, cut up, and generally cobbled up rifles to keep us busy for many years to come.
I also picked up an unfinished walnut JRS stock from Boyds Gunstock Industries, Inc., 25376 403rd Ave., Mitchell, S. Dak. 57301-5402, telephone 605-996-5011. Nowadays Boyds is probably the largest supplier of replacement wood stocks in the U.S. If you haven't checked out their web site, www.boydsgunstocks.com, you really ought to do so. They offer some very interesting and attractive stocks for an amazinG variety of firearms.
Boyds also offers a darn nice adjustable trigger for the Mauser. Since this will be a sporter, I opted to use one. While you can work with the old military trigger, a new sporter trigger adjustable for pull weight, sear engagement, and overtravel as well as having an integral side safety, makes a lot more sense.
Finally, I decided to use pre-threaded, short-chambered barrels as supplied by Brownells, 200 South Front St., Montezuma, Iowa 50171, telephone 800-741-0015. These barrels sell for only about $80 each, which is an amazing bargain. In addition, like all Brownell products, they carry a full guarantee. If for any reason you're dissatisfied with 'em, Brownells will cheerfully replace 'em or refund your money, no questions asked. What a deal!
The VZ-24 was first disassembled. In this case, that proved to be quite a chore. Over the years, I've pulled hundreds of barrels from receivers on all sorts of guns. The vast majority have come off with little or no problem.
This particular rifle had to rank right up there in the top three or four for being a royal pain in the rear. The darn barrel just didn't want to come off the receiver. I ended up having to put it on my lathe and make a relief cut ahead of the receiver. It took that and a lot of force to break the darn thing loose.
Fortunately the receiver and the barrel threads were in good shape. The locking lugs on the bolt were not giving me the amount of even contact with the lug seats in the receiver that I normally believe is appropriate, so I lapped the lugs and lug seats. This was done while the receiver was stripped and took only a few minutes.
If you ever decide to lap in your lugs on a bolt-action like this Mauser, keep in mind that it will alter the headspace to some degree. Consequently, you should always do this before you fit your barrel to the action. By doing it this way, you can adjust your chamber length to compensate for any changes in the position of the face of the rifle bolt brought about by the lapping.
While I was working with my action, I spent a bit more time examining the trigger guard assembly. Quite frankly, it was in worse shape than I initially thought. Sure, it could theoretically be repaired and used but I just frankly didn't want to spend the time necessary to do this.
Besides, during one of my periodic "clean and sort" sessions in my shop I ran across an all-steel commercial trigger guard assembly. What was especially neat about this unit is that it uses a detachable box magazine! The bad news is that the company that produced this item, Whitetail Manufacturing, Inc. in Williston, Vt., no longer produces this product.
In fact, I learned that they stopped production about eight years ago! That's really too bad, as it's a darn nice unit. I don't know of anyone else that offers an all steel replacement trigger guard and detachable magazine for the 98 Mauser.
In any event, I decided to use the Whitetail guard and magazine. It'll add a nice unique touch to the rifle and save a lot of time. I also noticed that it actually fit the Boyds stock better than the original military trigger guard! I have to admit, that really surprised me.
There were a couple of modifications I wanted to make to the receiver before the barrel was installed. First, I wanted to reshape the rear receiver ring and remove the charger or stripper clip guides. Since I'll be installing a scope, the clip guide would be unusable. Also, it just makes the receiver look nicer to have these projections removed.
While it's technically possible to reshape the receiver with nothing more than a file, I wouldn't encourage anyone to do it that way. For one thing, it's extremely difficult to keep everything even, level and uniform. Ideally I would want to use a surface grinder to do this job but I don't own one and the possibility of me ever having one is fight in there with winning the lottery. It ain't gonna happen! So, how do you accurately reshape a Mauser receiver without using a surface grinder?
Fortunately a fellow by the name of Mark Hendricks solved this problem for all of us. Mark and I worked together years ago at Brownells. While we were there, Mark designed a fixture that enabled a person to use a standard drill press to reshape a Mauser receiver.
This fixture, which is still carried and sold by Brownells for around $115, is absolutely fantastic. The receiver is mounted on a mandrel that in turn is supported n either end by the fixture. The mandrel and receiver can rotate within the fixture, yet Can also be held in a fixed position at any point by using two clamping screws.
In use, the receiver is placed in the fixture and with the use of an angle gauge, is precisely set at a 30[degrees] angle. A special cup-shaped grinding wheel is placed in the chuck of a drill press and the fixture positioned under the cup.
To make sure that my receiver was always positioned consistently under the grinding cup, I clamped a fence or guide to the drill press table. Although I used the fence from my bandsaw, you could use just about anything. A steel ruler or a straight piece of steel bar stock would work just fine.
Before beginning the actual grinding and reshaping of the rear receiver ring, you should make darn sure you're wearing safety glasses. The grinding stone was set up to turn at 3000 rpm, and it generate a lot of sparks and throws off many small particles of abrasive: You don't want any of that stuff in your eyes! It's also a good idea to wear protective gloves.
By the way, be sure to check the label on any grinding stone you use for the maximum rpm. You definitely don't want to exceed the manufactufer's recommendation. If you do, there is a darn good chance the grinding wheel will come apart while you're using it! My cupped grinding wheel had a maximum rpm recommendation of 7000 rpm so I was well under that.
When starting, turn the drill press on, stand back, and let it run for a minute or so before engaging the grinding wheel. If there's a problem with the grinding wheel such as a crack, you want to be out of the way when and if it lets go or breaks up! This also holds true for standard pedestal-or bench-mounted grinding wheels.
They will on occasion break or, as some folks describe it, explode due to a combination of centrifugal force and an unseen crack. So, treat all grinding wheels with a lot of respect and care. If you don't, sooner or later you'll have problems. And yes, I've had a grinding wheel "explode" and no. because I was taking the proper safety precautions, I wasn't hurt. But I did end up with a beck of a hole in the ceiling of my shop!
I initially had set the receiver at a 30[degrees] angle. This is the generally accepted standard for the angle of the rear ring on a commercial Mauser. The idea is to make two identical flats on the top of the rear ring and then join these two flats with a radiused or curved surface. It's important to try not to remove too much metal with each pass.
I lowered the cupped grinding stone until I just began to contact the raised metal of the charger guide. Once l had contact, I slid the fixture and receiver under the wheel. I moved it back and forth and at the same time I held it against the "fence" I had clamped to my drill press table.
Use of a fence at this point is actually optional. You can get away without it since all you're doing is making two flats. However. when you move on to the second step where you're joining those flats, a fence will be an absolute necessity.
In order to have both flats equal on either side of the rear ring, I alternated making grinding passes on the right and left sides. I would first grind down a bit of metal on the right side. Once the wheel was no longer contacting the receiver, I then repositioned the receiver.
It is important always to use the angle gauge to ensure the receiver is always set up or positioned in the same manner time after time. Once it was repositioned with the left side up, I would make a few passes on that side until the wheel was no longer contacting the receiver. I did not change the height of my grinding wheel until both sides of the rear ring had been ground. By doing this, I was able to keep both flats at an equal height.
Once the cupped wheel was no longer hitting the metal, I lowered the drill press quill just a bit; probably no more than a few thousandths of an inch. On my press, this was done by raising the drill press table. The process of grinding was then repeated until I had a nice flat, smooth surface on both sides of the rear receiver ring.
One note of caution when working on the left side of the rear ring; be darn careful you don't hit or contact the stud that holds the bolt stop. If you're careful, you can avoid any damage to this stud.
Also keep in mind when working on the left side of the rear receiver ring, you want the flat you create there to match the flat on the right side. Basically, you don't want it to be larger or lower than the other. Generally you can do this by just making a note of how far down you have positioned the grinding stone on your last pass on the right side.
Also, after making your final pass on the left side, reposition the receiver without moving the grinding stone and make one more pass on the right side. More often than not, that'll do the trick.
Be very careful as you do your grinding. If you lower the grinding wheel too much and try to hog off too much metal, the wheel can and will grab your receiver! Make very small incremental adjustments to the height of your wheel as you work. Don't try to rush it!
Take your time and work slowly and remove a minimal amount of metal with each grinding series. Also, aside from the safety issue, if you make shallower grinds you'll end up with a much smoother finish. That'll pay off when you're polishing the receiver prior to bluing.
The only thing left to do now is to take care of the area on the top of the rear ring between the two flats. After forming the flats, there remains a small pointed projection at the very top of the rear ring. This needed to be ground down for a uniform, smooth surface.
I began by clamping a steel yardstick across the top of my drill press table. This ruler acted as a fence and helped me guide the fixture as it passes under the grinding stone. I positioned the ruler so the top of the receiver was centered about a quarter of an inch or so to the inside of the outer edge of the grinding stone.
I started out with the stone set at the same height as it was on the last pass on the two flats. This would not be changed. I also checked with my 30[degrees] gauge to ensure that the receiver was initially set up properly. I wanted to make sure that before I began this last step that the receiver had not shifted.
After this last check. I loosened the clamping screws on the receiver mandrel and carefully rotated the receiver clockwise just a few thousandths of an inch. The receiver was turned so the right flat dropped down just a bit. The clamping screws were tightened and the fixture moved against the ruler.
The drill was turned on, allowing the grinding wheel to spin. I then slowly fed the receiver into the grinding wheel. The rear of the receiver was fed in first. My objective was to make a series of very, very small overlapping grinds the length of the top of the rear receiver ring.
The smaller you can make these overlapping flats, the less hand polishing you'll later have to do. The trick to all this is to rotate the receiver no more than a few thousandths at a time. Don't rush it or try to take off too much metal with each pass. Gradually, you'll have rotated the receiver to the point that the receiver is set up at 30[degrees] under the stone, and the surface of the left flat is parallel to the underside of the stone. At that point you stop! You're finished!
I realize I've provided a lot of detail about the use of this grinding fixture. However, I believe it's one of the handiest and best gunsmithing fixtures you can have in your shop. It's unique in that it allows you to obtain results with a simple drill press that you could only obtain otherwise with a milling machine or a surface grinder. It's amazing what you can accomplish with this thing. If you don't have one, by all means, check out the Brownells catalog for this as well as many other great tools.
With the rear ring of the receiver suitably modified, the next operation will involve both a bit of metal work and wood work. The rear tang of the receiver needs to thinned down just a bit. This also allows the wrist area of the stock to be thinned for a smoother, narrower, more custom look.
Now don't get me wrong; the Boyd's stock as I received it is pretty darn nice. However, if you look at the stock where the rear of the receiver tang is located, you'll see a small, narrow slot cut into the wood. This is to allow for clearance for the bottom of the cocking piece as the bolt is opened and pulled to the rear. It's pretty common and you'll see this on a lot of stocks.
The only problem with it is that the sides of the slot in the wood will generally get chipped up over time. Also, there's still a problem with the overall lines of the stock in this critical wrist area. It's just too fat!
The way to deal with that is to reshape the top of the tang. This can be done easily with a file. I went ahead and installed the receiver in the stock. With this stock, the receiver dropped right into place with no need to do any further inletting. I also installed a trigger guard so I could use the two guard screws to hold the receiver securely in the stock. I then clamped the stock in my padded vise and began reshaping the tang.
I used a flat bastard file for this work. As I worked on the tapering the tang, I also cut into the adjoining wood. It was important to keep the lines of the stock smooth and at the same time not make the pistol grip appear too thin or irregular.
There's no secret to doing this work. Just go slow and step back from your work frequently to check the shape of the pistol grip and tang area. Also, run your fingers along the stock wrist as you work. If there are flats or angled areas developing, you'll often feel 'em before you can see 'em. As long as you constantly watch what you're doing, you shouldn't run into any problems. All in all, it took no more than 20 minutes or so to complete the reshaPing of the tang and the stock.
Finally, after finishing up the tang modification, I went ahead and did the necessary inletting for the commercial detachable box magazine trigger guard. When reshaping the tang I had just used an old military guard. The new bottom metal had a catch for the box magazine. This projected about a quarter Of an inch above the inside of the bottom metal. Of course, there was no clearance for it in the stock.
It was just a matter of coating the mag catch housing with inletting black and then pressing the bottom metal into the stock. The impression of the catch housing was easily seen on the wood. I used a number of small sharp chisels and gouges to cut out the excess wood and provide the necessary clearance for the catch housing.
The only thing I really had to watch was to be careful not to remove too much wood. In situations like this some folks will just plain go hog wild with a Dremel tool and cut out way too much wood. Not only does it look bad, it's poor workmanship and it can weaken the stock. You don't want to remove any more wood than you absolutely must.
Once that was completed, I was ready to begin work on the barrels and the barrel nut. However, that'll have to wait until next time (12/10 issue).
Until then, good luck and good gunsmithing!
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|Date:||Nov 10, 2009|
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