In an email I was asked about color case hardening a Mauser '98 action.

This is a Persian action that houses a .416 Ruger and the action has already been heat treated at Pac Met to 37Rc.

I'm quite reluctant to mess with the heat treating by adding colors to the action. Has anyone done this and if so what was the results?

Well, considering the heat that is needed for color case hardening, you will undo what has already been done. Also, there is a good chance you will experience warpage.

If you search this forum and the big bore forum you can find where it has come up several times. I am often the only person who comes out against it, and continue to do so today. Case coloring everything is a fad that will pass, but none too soon for me. Items should be case hardened when those particular material properties are needed.

And BTW-the case coloring will negate the heat treating that the action has righ tnow. The action will have new properties after the case coloring, and the properties will not be condusive to long term safe shooting.

quote:

Originally posted by Marc_Stokeld:
And BTW-the case coloring will negate the heat treating that the action has righ tnow. The action will have new properties after the case coloring, and the properties will not be condusive to long term safe shooting.

Thanks Marc.....I was also of the opinion that "coloring" would draw the heat treating and diminish the strength of the action and advised against it.

I've seen some pretty Mausers that were case colored and assumed that those that did it were "informed" but maybe they weren't pushing 60 KPSI either!

I also thank rem721 for his comments too!

Another thing I forgot to mention is that you can only heat treat steel so many times before the grains grow too large. When this happens, the steel becoems both brittle and weak and the part is useless for a gun. The only way to get them small again (small grains are good!) is to forge the steel. If there is a way to reforge a Mauser action, i sure have never heard of it!

People who case color usually say 3 times is hte max. So once at the factory, once for a rebarrel or whatever, and then one more time down the road. Each additional time you heat up the steel, you exponentially increase the chance of warpage. Ask people who reassemble double shotgun actions after their second treating. The term for it is "hard fit." It is supposed to mean that the parts are "hard," but folks who routinely do it will tell you that the actual process of getting the works back together is "hard."

Almost all old double shotguns need to be case hardened at a temperature range that also produces the "cool" colors. If soemone has annealed and reshaped the action, or had it engraved, then it needs to be recased. Otherwise, I feel strongly that it should be left alone. Every time you heat an action like that, you are screwing with the molecular structure of the steel.

"only heat treat treat so many times ..." Large grains make for brittle steel but those grains can be reduced in size by re-heat treating .Each time you HT you form new grains. Of course re-HT will change or destroy the color !....Howe describes the process as heating to about 1400 F for three hours .Higher temperature would certainly accelerate grain growth. Grain growth is far more dependant on temperature than time.Modern case hardened things like bearings and gears are re-HT'd after adding the case but they don't care about color !! ..In the old days they just used carbon steels [.10-.20 C]..About the nicest clor case hardening I've seen is on my Lone Star Rifle Co rolling block which is made of 8620 and colored by Turnbull IIRC. ...The warpage problem is another thing .Some items can be put in a fixture to prevent warpage. Certainly repeated HT will multiply the problem. ... I never thought a Mauser looked good with color , only a slab sided gun like a single shot ....I'd also keep the pressures well within reason.

Mark: I'm with you...I really get nervous about color casing a receiver and will always get a disclaimer. Turnbull does a lot of this and I've truthfully not heard of a "whoops". I have a letter from H&H in which they declare in no uncertain terms that heat treatable steel must NOT be color cased...would I do it to my own guns....NEVER! I have a Brno that someone welded up a couple holes in the ring...crappy job and I'll have to re-do. I'll be sending it to Pacific Heat Treating afterwards...trust their work!....but.....I'll light off several hot loads before approval and delivery to customer...some things just should not be f...ed with.