Home Forums Hunting & Shooting Gunsmithing Mauser Heat Treatment

The key words here are Rockwell hardness. Rockwell testing is great for metal that is heat treated and is hard all the way through. As discussed, Mausers are case hardened which is better measured by other methods, Schorr(sp?) for one. Unfortunately, to get an idea about the true case depth, the part has to be sectioned. If you are unsure about the actions, buy some headspace gauges and check every so often. If the headspace is opening up, the action is too soft, allowing the lugs to set back. A soft action fails slowly through metal displacement and stretching. A too hard action can fail catastrophically, i.e. Low number 03's.

Rule of thumb German made mausers from 1934-1943 are the strongest and more uniformly heat treated. Use them as is.

Early ones are a crap shoot. Blanchard's does great work at a decent price, especially in volume. I know from personal experience.

Pacific Metalurgy gave a very nice price for volume M98 mausers when I was searching and they have a great reputation as well, but I have no personal experience.

I'd probably send them in for reheat treat but as others have said if they have no lug setback they are probably fine as is unless building a high pressure hotrod.

ETA: Jerry Kuhnhausen's books are gospel for many gunsmiths. There are more than one way to do things and well.

RC testing probably not necessary on mausers. Try to scratch the recoil lugs with a carbide scribe. If it scratches easily have the treated.

It may be overkill but I am a firm believer in having them re heat-treated. I use Blanchards; they do a nice job and they have an FFL. Pacific apparently doesn't have a license and I've seen a 1909 they did that was significantly warped.

On the current 1909 that I'm doing, I had it annealed before I did the machine work, then had it re heat-treated and did some clean up work on the lathe. Adding a couple of hundred dollars to the cost of the build was a non-factor in the grand scheme of things.

I'm not a gunsmith, just a hobbyist.

If I remember correctly, weren't the early 98's made of low carbon steel and as such impervious to heat treating other than carburizing? What kind of alloys were used in later ones from the 30's-40's, from such makers as Mauser, Steyr, BRNO, etc.? Do these folks who do re-hardening conduct a chemical analysis before throwing them in the furnace, or perhaps a chart of such exists which they consult first?

Blanchards has done a lot of mausers. They know what they are doing. Their process is correct for mausers. Mausers are strong because of design, not materials.

They did some pre64 Win 70's for me and used a spectrum graph or something to determine alloys. They also provided me with that analysis as well as before and after RC values.

I like this idea. for three reasons.
1)I am having to do the feed rails for 358NM and D&T for scope mounts. (Hopefully I will not have to touch the feed ramp other than polishing.)
2)I don't know the history of the receiver.
3)This is a 64,000 psi chambering.

I think I would rather spend the time and money and have confidence in the action. If I were thinking ahead about this, I might have been a little more aggressive with the bolt lug lapping.

This is obviously not going to be a weekend project.

More overtime in my future...

On a positive note, I finished shortening and re-welding new Large Ring bottom metal to fit my M38 Swede and got it all inletted into my Bell and Carlson stock over the weekend. I got to take it to the range for the first time in over a decade. It was good to get it back in the safe from leaning against the wall in the man cave. The bottom metal came on the action I bought for the 358NM project but was badly pitted. I got Mark X metal for the 358. After the chop and re-weld, I went after the pitting with the MIG welder and it came out pretty good. Since the Swede is a "well done shooter", the result was good enough for Cerakote to cover the remaining flaws. Still got 5 rounds in the mag well after re-assembly. All in all it was WAY cheaper than new Sunny Hill bottom metal.

The Swede is heading out for metal finish soon. I am on Ed Lapour's waiting list for a 3 position conversion some time in January. After that, it gets a bedding job and the stock goes back to B&C for their two-part paint job. Then it's done forever.

I don't think you'll regret your decision.

Another factor to consider is when changing out the bolt handle, as most Mauser conversions include, did the welder soften the cocking notch? If you re-heat treat/carburize, it won't matter.

I have been sporterizing Mauser rifles since 1965.
I currently have 89 Mauser projects on the spreadsheet, but it feels like 200 with the space it takes to store them.

I have some theories about Kuhnhausen's books:
1) No one person could write a book as bad as his book on Mausers. It must be a collection of lecture notes without the diagrams, that went to print without editing.
2) No one person could write a book as good as his books on double action Colts. He must have been spoon fed information by personnel at the Colt factory.
3) R.A. Walsh, a retired engineer like myself, wrote his only book on the topic of Mauser sporterizing, partially with the purpose of righting the wrongs of the Kuhnhausen book.

If I were tasked with duplicating a Mauser's heat treatment, I would find a scrap action of the variety in question, and try scratching the bolt lug area with a knife blade - not a carbide scribe (carbide is too hard). If the knife does not cut it then it probably is case hardened.

At that point then I'd take the scrap action to a metallurgical lab, show the metallurgist what I have in mind, and ask him to determine the case depth of the area in question. He will be able to use a wet wheel to cut the metal cold and not affect the temper. Then he'll make a mount, polish & etch it, and begin using a Knoop microhardness tester. Obviously, the test is destructive, which is why we use a scrap action.

The Knoop tester makes an extremely small indentation in the polished surface, and the microscope built into the tester allows the operator to evaluate the hardness in very small areas - like the area directly below the case hardened surface.

If nitrided, the case depth will be extremely thin, like maybe .001-.005" thick or so. If it was carburized, then the case might be .010"-.030" thick. Explain to him that you want to measure the case hardness, and case depth, and he'll take & report a number of readings. The cost will be probably somewhere between $200 & $500 for the test. I would also do a chemical analysis at the same point, to determine the chemistry of the steel, to share with the heat treater.

Normally when I specify case on a large tool, I'll specify, "Rockwell C50 minimum in case, minimum case depth .010" to get a balance of wear resistance and toughness. Just guessing, I'd expect something similar for a case hardened Mauser.

You're kidding? Why? Send your receiver to Pac Met or Blanchards and leave it to them. They have done literately thousands and know how to turn on a furnace.
Now if you did this, what part of the receiver would you saw off to do all of this checking?

aahhh...well...okay some folks like a mystery, I guess. Since metalworking and heat treating has been my business for 30+ years, I think about the details of such things.

Case depth and case hardness are things that can be measured, and I've seen a lot of folks ask about how Mausers are heat treated, but no one has ever known the answer. Some guys may indeed know the details, but they aren't talking.

If you're trying to measure the case on a particular surface, on a scrap actionyou make a cut perpendicular to the surface. Then the new section is polished, until you can make a mount, and then take microhardness readings to determine case depth & hardness.

Don't have a scrap action to test? then proceed as you see fit.

One reason why it would be interesting to know the details, is because, if the original case is very thin, then you can duplicate it with salt bath nitriding, which usually causes little if any distortion.

If I knew nothing, I would start by researching the mauser receiver as it pertains to metal treatment "case hardening". I think your search will show that parts of the receiver was case hardened and not the whole receiver. There is extensive info on The Accurate Reloading forum on this subject. If you like searching for good info and like to read, search them out. I've had a lot of experience with barrels and dies that have been Melonited. I've had a great amount of success with it.

OK, start with this D' Arcy Echols and Tom Burgess.


D'Arcy extract:

Twice in one day, Hand me the flack jacket! While attending the School of trades in Denver, We were told that any 98 rebarreled to a modern caliber should be re-carborized .030 to .040 deep so the surface hardness was around 36-40 RW C. The bolt a few point higher 40-44. They converted more than just two or three. Later when I opened my own shop I built 2 rifles chambered for 270 Win. and fell into the mind set that I now refer to as "how can you re-heat an action if you don't have a clue as to what it's made from" One was a 1909 and one a Radom. I had the rifles back in my shop years later and both had been set back enough that I had to set back the barrels the required amount clean up the lug seats and then sent both actions in to be recarborized and have not had a problem since(REMEMBER SAME REAMERS, SAME GAGES, SAME RIFLE). Do you know of anybody that has a 270 that won't try to get 3100 fps with a 130gr bullet? Ray sure won't leave the 404 at original speeds. The number of rifles I have had in my shop for some sort of repair or restoration that have set back is long indeed. This list would include the hallowed 98 square bridge actions, vz-24, 1909, 1908, and one FN in the white straight from the factory that I failed to check with the rockwell tester. I chambered the FN to 300 Win mag and it set back .015 in less than 200 rounds. It has since been hardened and to my knowledge has not move to the rear at all.Take it for what it's worth.

I have every 98 that I now use annealed dead soft, do 90% of the machine work that is required. Then it is sent in to be re-carborized as described and then finished up. Some 98 actions are probably OK to use as is the 1935 being one of them. But why take the chance and why waste all those end mills on an action that is glass hard on the surface or have to eat the repair when it shows up back in your hands.

I did have two 1909 action destroyed to get an idea of the steel composition. The results were as predicted and I now use the 1909 for any project that requires a 98 in a standard length Magnum, no I don't use them for the 375 H&H or similar lenght round as the action just gets to sloppy for my taste. Russell Wilkin the shop manager at H&H (ever hear of them?)requires all bolt rifles built on the 98 actions to be re-hardened. Go figure. Got to give my girl a bath!

TomBurgess extract:

Eldeguello, Considered as a whole there is not enough difference in the steel recipe for military '98 mausers. The reason for this is that machining with a predictable cutter wear, smoothness of finish from the machining and the final carburizing process leading to proofing all entered into the acceptance of any lot of steel. The steel does not exactly correspond to North American AISI SAE or ASME lists and chemistry's. The closest we have is the 1100 series. Prior to WW II there was a group called "Machinery steel" If you can find an old Ryerson book of that era you may find that this group had about 3 varieties from arouind "18 carbon ,25, 30 and 44 carbon". Starrett used the low carbon steel to make many of their tools "case hardened in colors". Others did similar things with it. The Various carbon grades of this steel is still available in various parts of Europe. For the Mausers the Spec was 27 to 33 Carbon. The significant alloying agent was Manganese. There seems to be very little difference from as early as 1901 to about 1942 in a carbon range of 27 to 33 and a Manganese spread from 115 to 140. The Manganese helped in the carburizing process because it allowed deeper penetration of the added carbon and softened the boundary definition in the carburised case. A smoother transition from case to core if you will. This also allowed a finer grain structure, and because the manganese tends to make up for the bad effects of too much sulphur ( up to a point) the Sulphur number could be higher allowing for smoother surfaces from machining, less wire edges to be trimmed at corners and so on. Carburizing these, particularly in the carbon monoxide gas process,is quite straight forward and does not require fancy or exotic methods. For those who have had readings made and point to all sorts of trace ammounts of various other elements I have to say that in carburizing these it makes damned little difference. Those actions made close to Czecoslovakia and or in that country will often have many elements in the mix and some of these can be said to add to the strength of the receiver and bolt.
This had more to do with the cokeing coal used to make the original pig -iron. These elements were sucked up by the iron in the melt, and could include Uranium, and Zirconium among a fairly long list of neither add nor subtract from strength elements the combination regarded as a whole entity. The Argentine made '09s do seem to be different. In a heat lot of 10 The as quenched Rockwell was noticably higher and required almost 100 degrees more heat (F) to achieve the desired Rc hardness. Conversely some crude Spanish made actions complete with Mauser Logo and "standard modell" plus a certain importers mark had to be cooked for additional time to achieve desired hardness. Subsequent test of another from the lot indicated 15 carbon steel. The machining was crude enough to indicate it had never been to the Fatherland. Experienced heat treaters check the hardness after quench to determine the correct temperature for the temper draw. In some schools the process is then known as heat-treating. The original method was Pack hardening. The carbonaceous material at the heat used liberated carbon monoxide gas which was absorbed by the iron. At quench this material flaked off in the quench medium, This was saved and applied in areas not needing great depth or hardness of case. New material was used in the locking lug area the bullet ramp and underside flat up to the recoil lug and also on the extracting cam of the bridge. Recycled material was used every where else on the exterior, but recycled plus new material was applied to the feed well and most of the rest of the receiver subject to wear from the bolt. The tang flat where the trigger humps rolled also got a good gob of new material. This was labor intensive. To go to Copper plating as a stop off would take double the time and was totally unnecssary. Same for the baked on copper bearing paint that the German's had available. The early powders used in Europe did not have the same burning characteristics as did Brit. Cordite or the American cylindrical powders. translating a Rockwell number to yield tables in "the book" are fine for static loads but not worth a damn for the Dynamic loads produced by modern powders particularly in so called reduced loads- the 25-06 being one come to mind that can produce great violence so loaded.

This is a thread that goes with the above.

http://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/746100356?r=419108456#419108456

Remember, searching is your friend.

Thanks. But neither of those references states the depth of case, and hardness of the case, on original Mausers. The information on chemistry confirms what I have read before.

I've never joined AR, but I'll try searching there and see if there is more detail.

Oh well

I have built a few Mauser sporters using late pre-war BRNO actions, and kept them all in x57 calibers. So far no set back, but then again I don't hot rod any of them. I have an old sporter that was built on a WWI Gewehr 98 action, that I re-barreled to .30-06. So far, after a couple thousand shots, no setback, but again no remotely heavy loads either.

I think the main cause for concern with M98 actions these days stems from the pervasive need for speed. Guys are building guns around these old actions for cartridges they were never intended for, and subjecting them to gut-wrenching pressures. The comment above concerning a .270 owner sooner or later going after 3100fps w/130 bullet is an example. Likewise the OP's intention of barreling one in a .30 Magnum. Were I to build yet another Mauser sporter I probably wouldn't bother with re-carburizing it; but then again it'll be in a pretty sedate caliber that I won't be stretching the limits of. If a next owner of any of my Mausers gets carried away with loading them hot and suffer setback as a result, that's on them.

M98 Mausers make up into beautiful classic sporters. Guns which excel in the game fields when chambered in "normal" calibers as well now as they did 100 years ago, which is pretty damm good. Why push the envelope for just a few more yards maximum range? If one is hell-bent to push that envelope, I posit that there are a lot of much more suitable actions to use as a basis for that. (Or better yet, work on one's field skills and physical fitness to get in to 2-300 yards from that animal instead of trusting to technology and a flabby butt to whack it at 500 yards.)

But I do hear you on old rifles in high intensity cartridges. When you find a really interesting old Mauser that has been chambered in a modern caliber, it's a valid concern to figure out what to do with it. Whether the bolt has set back, or whether you just want to decide how to load for it.

I eyed a custom G33/40 this week, in .257 Roberts, which I'm debating about buying. And I inherited a couple of sporterized Mausers from Dad. They'll get moderate loads. Ditto the 1920 Savage.

I stand corrected. I don't have any experience with the LGBT calibers...

I thought .303's went along with 3 dollar bills?