Mr. Belk,

Someone here mentioned a nice critique you did on the CZ 550 over at huntamerica, but I'll be darned if I can find it. Would you mind posting your impressions here (not sure how long it was) or just copying or providing a link?

Also, could you maybe comment on your thoughts of this action as a foundation for future custom work. And maybe how you feel it stacks up against other current manufacture CRF rifles in terms of safety, quality, and design. I apologize for the redundancy if these things were covered in your initial critique.

Thanks in advance for your time and expertise,
Bob

I'm not Mr. Belk, but I did sleep in a Holiday Inn Express last night...

Try this link for a review from Mr. Belk

http://www.huntamerica.com/wwwthreads/showflat.php?Cat=&Board=UBB8&Number=160856&Forum=UBB8&Words=CZ%20550%20&Match=Entire%20Phrase&Searchpage=1&Limit=100&Old=allposts&Main=16 0754&]http://www.huntamerica.com/wwwthreads/showflat.php?Cat=&Board=UBB8&Number=160856&Forum=UBB8&Words=CZ%20550%20&Match=Entire%20Phrase&Searchpage=1&Limit=100&Old=allposts&Main=1 60754&

[ 04-11-2003, 00:58: Message edited by: Badboyz ]

Can anyone pin down the CZ 550's metallurgy more tightly than "alloy steel"? I'm toying with the idea of doing some ferritic oxy-nitorcaroborization experiments on a CZ 550, but I'd like to know where I'm starting from before beginning such an experiment.

Infosponge. Why Carbo-nitriding? What is the expected quantum leap gain? Less wear in an Iraqi type sand blizzard?

Mr. Burgess,

In essence, what I am investigating (just on paper for now, maybe in steel later) is whether there is a feasible and economical way to reproduce with current steels and heat treat processes the case hardened actions that you, Jack Belk, and other respected gunsmiths daydream about. My goal is an action that matches the core toughness of a double heat treat Springfield or the best military Mausers or a 4130 action with a core hardness of around Rc30. This core condition to be acheived with a surface hardness of Rc60 or better, and with an excellent magnetite/"rust blue" finish.

At barely more than first blush, it looks like fluid bed oxy-carbonitriding ( http://dynablue.com/dynablue.html ) may provide just that ideal combination. Cost of this combination heat treat and finishing process is still an open question, but I have hope that it can be done for the same or only a small amount more than having a gunsmith rust blue by hand. If that is the case, then finding an inexpensive action in a suitable initial state would be the next step of the experiment. Hence the interest in the details of current CZ metallurgy. Certainly there are inexpensive Mauser actions (e.g., VZ-24s) available, but I'm shying away from them because I don't think it is possible to know the details of their metallurgy without destructive analysis. Starting from an incompletely known initial condition would queer the whole experiment. Starting from a new Montana 1999 4140 action would be another option -- particularly if I could get one tempered to about Rc35 instead of the usual Rc42.

If it all works out, the result would be an extremely tough, current production action (core hardness Rc32-38 in 4140), with a nitride diffusion layer of about 0.02" and hardness of core+10Rc, a white layer of about 0.001" and hardness of Rc75+, and a 0.0001", very smooth "rust blue" finish. With various additions to fill in the pores of the finish (either as part of the heat treat/finish process, or applied by hand afterwards), various levels of corrosion prevention (up to and exceeding that of hard chrome) could be acheived, along with low coefficients of friction. In fact, because the process causes very little change in dimension or surface roughness, and because it can be applied regardless of part geometry or line of sight, it may well be possible to effectively "rust blue" and anti-corrosion treat the bore as well as the exterior of the rifle barrel.

In other words, the goal is a rifle that meets or exceeds the safety and toughness of the best pre-war actions, meets or exceeds the anti-corrosion properties of the best current stainless steel rifles, doesn't require any special machining compared to current 4140 rifles, operates slick and smooth without galling concerns, looks good doing so, and doesn't cost more than having a gunsmith rust blue by hand off-the-shelf metalwork.

Ambitious? Sure. Doable? I don't know. That's why all the questions.

and now that we are completely off topic...

I would suggest one start with a bar of desired alloy, machine to rough dimentions, polish here, hone there, and then attempt your experiments. This would allow you to control, and repeat I might add, ever variable. Future, you could arrange various depths/thicknesses, and then under destruction testing, have the hardness independantly verified...

and now back to cz550....

JB?
jeffe

Infosponge,

May I suggest a university in your area. Find out which department has an electron microscope and have them do an atomic profile. Takes about the time to pump the 'scope down. This will give you a complete breakdown of every element in the alloy and the percentages. If there are none in your area, you can mail a piece to me and I will have a classmate run it.