I agree with GB that hand held XRF’s are the best way to test alloys. The problem at least in San Diego sized cities is finding someone with one of these devices who would do the test inexpensively.
I think that 2152's method might be the best alternative approach for steel and I'll try this method next time. Thanks.
I also took the course on CCH at Lassen College and CCH'ed an Italian made Remington rolling block action. I ground off a small spot on the bottom of the action and used the schools hardness tester to check the action's hardness. The hard top surface was less than .010" deep and the rest of the action wasn't hardened. 
However, several test pieces, using pre WW-2 M-98 magazine floor-plates, thought to be made with low carbon steel, were through hardened and brittle. This has led me to file test any thin CCH'ed parts.
Otto

I have reached out to Rodney in regard to the type of steel of the kit. Waiting on a response, I know he’s retired. Does anyone have recommendations for a heat treat house or qualified individual? 

Logan

Logan wrote on Jan 5^th, 2026 at 6:18pm:


Contact Al Springer at Snowy Mountain Restorations. Al should be able to tell you if he can heat treat it or color case harden it.

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Logan wrote on Jan 6^th, 2026 at 6:04pm:


Just for clarification, Al says 8620 doesn’t need case hardening?   
Bob

Case coloring is just case hardening that ends up with nice colors.  The surface still ends up extremely hard and wear resistant.   
Bruce

Al once told me that there are folks that do coloring without case hardening.  
He said his is always color case hardening. Don’t know who he was referring to.
Bob

ssdave wrote on Jan 7^th, 2026 at 12:04am:


That’s interesting Dave, their colors are nice.

Bruce, I agree.  But, in the context of the statement, as Logan understood, it sounded like Al was talking about two different process. 

What I know about case hardening could be dangerous, but here is what I understand.  Anyone correct me if I’m wrong.  I have a furnace but still hire people to do mine.

Some folks take the parts to critical, let them soak for a period of time to allow carbon absorption and then quench.  The problem with this, is our firearms parts can warp.  My guess this is more an industrial process, that give little or no color, but deep case hardening.

Some folks take the parts to critical, let them soak to allow carbon absorption, but then lower the temperature below critical for a period of time and then quench.  While this may not eliminate warping, it would great reduces it.

My thought is if you keep the parts below critical, let them soak and then quench you will probably get very little or shallow case hardening, but will get colors.

If someone were to take a piece of 4140 and take it to critical let it soak, and quench, you would get glass hard steel.  I don’t have a clue what would happen if you lowered the temperature below critical, soak and then quench.  Might still be very hard.  And, there probably would be no color.

8620 is very well know for being a good steel for color case hardening.  This is the reason for my previous question about what Al said about 8620 only needing case color.

Pretty sure I read an article a few years back where a guy had an action made from 4140 or similar steel and wanted it color case hardened.  Everyone knew you couldn’t do this, but apparently Turnbull figured something out and did get it colored.  Don’t know how they hardened it.  They may have hardened the steel, then tempered it and used external heat or even a chemical for the color.

All this is the reason it is critical to know the steel being used.

This explanation is greatly simplified and in reality is much more complicated.
Bob

That all makes sense, there are some heat treating facilities around me that anneal and case harden, along with a multitude of other processes. I thought about asking them if they do gun parts, assuming that the case hardening process would color. If it doesn’t, it could be a better option when the plan is to nickel plate, if it’s cheaper than Al. Thanks all for your input, learning a lot.

Logan