View Full Version : Action heat treat

November 23, 2010, 10:43 PM
Anybody recommend a place that can heat treat a too soft Mauser action. I was having it fitted for a new barrel and the barrel maker said the action was too soft. The old Rifle is in extraordinary condition otherwise and I'd love to be able to use it again. The throat is gone in the current barrel. So, who does a good job at this?

James K
November 23, 2010, 11:25 PM
What kind of action is it? What caliber do you want to use? Some actions, like Spanish-made 1893's, are fairly soft, but will last a long time with pressures in the range they were designed for.

I doubt you will find anyone who will undertake to heat treat an action made years (a century?) ago from steel of an unknown composition and quality.

If you want to shoot ammo that is beyond the pressure level of that action, the answer is simple - buy a new rifle or a later action and don't take any chances with your own safety.


November 24, 2010, 12:00 AM
It's a K98k action. The rifle is chambered for the 219 Donaldson Wasp. Worst part is I decided to rebarrel and bought a bunch of brass for it from Buffalo Arms so I already have a few hundred in it just in brass. The old gun has double set triggers and a beautiful mannlicher stock of English Walnut. I was wanting to be able to shoot the thing again but it's starting to sound like a lost cause. It might just end up a mantle piece.

November 24, 2010, 12:27 AM
was it in a fire?

if the metal is soft a good distance behind the locking lug area and the receiver ring who cares?

November 24, 2010, 12:29 AM
was it in a fire?

if the metal is soft an inch or so behind/past the locking lug area and the receiver ring who cares?

November 24, 2010, 12:33 AM
There are companies who will HT actions for you .This is a carburizing and HT process. But other things have to be considered. If the rifle has seen hot loads you have to check if the lugs have set back ! Action and lugs should be lapped before HT. I don't have names but make sure you go to experienced , with good reputation.

November 24, 2010, 01:12 AM
The action may well be soft.Did the smith actually rockwell test it?Where did he test it? If I understand correctly,a typical Mauser was only spot hardened in critical areas,such as the lug area and primary extraction cam.
You may want to get a second opinion on this.
If you wore out a barrel without the headspace deteriorating,it may be the lockup is adequate.
Do be safe,maybe this action has a problem,but I do not expect hard rails and receiver rings on a Mauser.Does it show any evidence of setback?
Inside,where the bolt lugs actually rest,try a steel scribe or pocketknife or something and see if it will get a bite.
It would also be possible to rebarrel it in a modest pressure cartridge if it is soft
Turnbull color cases rifle actions.I have seen pix of mausers he has done

November 24, 2010, 10:42 AM
As far as I know the action has never seen a fire. The rifle is in pristine condition and appears to be a European maker although there is no name on the rifle. The 219 DW cartridge only makes 40,000CUPs of pressure so it's not a high pressure case. There is zero evidence of any set back or wear at the lugs and the action is like glass. Douglas did the Rockwell testing and I assume they have a clue what they were doing. Their note when it came back was that the action was soft, very soft and not even close to being acceptable. Up until I decided to do this, there was no sign of any issues with rifle. Brass can almost be reloaded without resizing, it is a rimmed cartridge. I would just like to get it rebarreled and be able to shoot it like it deserves.

November 24, 2010, 11:29 AM
Mausers were made of a low carbon steel such as a 1020.This was then carburized and hardened. You ended up with a hard ,wear resistant surface and softer but tougher core.
Re HTing , considering all the possible variables , would not have as hard a surface . IIRC mine ended up with 40-45 HRc surface.
Modern actions are typically made of an alloy such as 4140 through hardened to 40-45 HRc.

November 24, 2010, 12:09 PM
Anybody recommend a place that can heat treat a too soft Mauser action.

The problem with any 'after the fact' heat treat is determining the EXACT metal composition to design the heat treat.

Sometimes you can make some educated guesses, but it is still a bit if a crap shoot without running a composition analysis on the metal.

November 24, 2010, 02:50 PM
One of the heat treating outfits in Salt Lake City (Blanchard, IIRC) used to heat treat Mauser actions. Call and talk to them.

As above, military Mauser actions were made of fairly soft steel, then carburized to provide a hard, wear resistant surface (hard steel is wear resistant but brittle, soft steel is tough but wears easily). The carburizing only goes a few thousanths of an inch deep. Modern commercial Mausers (like the Zastava Mauser 98s) are made of better steel.

Make sure the action is ready to heat treat, and all surface prep is done before sending it to the heat treater. It will be easier to polish and drill/tap it before heat treating than after it comes back

And no, you don't need to know what kind of steel it is, carburizing even works on cast iron and modern tool steels. Carburizing goes deeper on soft steels and cast iron than high quality steel.

November 24, 2010, 03:01 PM
And no, you don't need to know what kind of steel it is, carburizing even works on cast iron and modern tool steels. Carburizing goes deeper on soft steels and cast iron than high quality steel.

If you actually care about the strength of the heat treated article you darn well better know what you started with.

It is easy to make surfaces harder, but that is often a marginal improvement in overall strength.

November 24, 2010, 03:24 PM
It is easy to make surfaces harder, but that is often a marginal improvement in overall strength


Carburizing is just a surface treatment. Makes the surface wear resistant but it does not go deep. Increases the carbon content by exposure to a carbon rich material. From one Watertown Arsenal Report, case depth on 8620 M14 bolts is around .01" inches. From another Watertown Arsenal Report, a table of 8620H mechanical test specimens, the case depth is .005 to .021".

Two thousandths of an inch does not mean much if the underlining material is soft and cannot be heat treated to a decent hardness.

This sounds like a project gun. You will spend less tossing this receiver and finding a nice new receiver to build a rifle.

You can buy M70 FN receivers from CDNN. Those are made from 4140 and are an excellent action. 308 bolt face though.


November 24, 2010, 03:29 PM
Agree with that it is a tough call. There was someone doing Mauser heat treating specifically years ago, but I can't recall the name. If you find someone who did that regularly, they might know the alloy well enough by your make and model year. But this is specialized work. You might try Jim Caudill (a.k.a., The Mauser Man). 740-965-2185 is the last number I had for him. I don't believe he does this kind of work, but having specialized in building Mausers would likely know if such a person is available. He might also give you a second opinion on your receiver strength. Your pressures are low and your case cross-section near the head is intermediate (.422"), so bolt thrust should be about like a .30-06 firing at 32,000 psi. But you need to check with someone more experienced with Mausers than I am to know where the line is drawn.

About the only other thing that occurs to me is that double heat-treating may work out on your receiver if the alloy can't be determined. Hatcher's Notebook describes the process, which was the intermediate method for Springfield receivers between the old hand heat treating and the nickel steel versions. Since the process draws the core metal back to about 1300°F, it is hard to imagine any alloy that would still shatter after that. A big concern with any kind of post production heat treating, though, would be distortion. You need someone skilled at it.

November 24, 2010, 03:41 PM
All of these old rifle receivers were made from plain carbon steels. The ones used in the Springfield rifles are well know to Americans because of Hatcher's Notebook.

The steel used in the single heat treat receivers and the double heat treat receivers were the same. Looking at data on Matweb, the low carbon steel used in these early receivers is not used for complicated parts, unheated it is used for rebar, if heat treated for medium duty shafts, studs, bolts and nuts.

I did a composition search and found AISI 1117-1118 steel, which is similar in composition to Class C steel. I could not find something that was just carburized and quenched . I found data for 1 inch round AISI 1118 mock carburized, reheated to 1450 F, quenched, tempered. This is similar to the double heat treatment. The Ultimate strength is 103,000 psi, yield 59,300 psi, elongation at break 19%. For something similar to WD2340 Nickel steel, which is an alloy steel, I found one inch round AISI 4820. For that material, mock carburized, 1450 F reheat, water quench, the ultimate strength was 163,000 psi and the yield strength was 120,000 psi, elongation at break 15%. It would appear to me that even the best of the double heat treat receivers have a low yield strength compared to an alloy material and less elongation before breaking.

Today, no one uses rebar to make a complicated and expensive part such as a rifle receiver, but that is what was used on all of these old military receivers.

Plus the problem is, the composition of the materials varied so much, how can you get the correct heat treat temperatures for the thing?

Even double heat treat receivers may be brittle. http://www.fulton-armory.com/LNSpringfieldLowRes.pdf