Refurbishing Chaparral 1876s

[kb466]

I have an earlier production Chaparral 1876 rifle that I am working on to get it to the point I am happy with it. Among the things I want to do is sharpen up and correct the lines on the over-buffed receiver. The trouble is that it is made of 4140 steel and is hardened as well-- a file just doesn't want to cut into it. So, I am thinking of annealing the receiver to get it to a point where it can be more easily worked. When done, I will be having it charcoal blued rather than case hardened. As I understand the process, I will heat it to a dull red and let it cool slowly. Would it work just as well to heat it to a lower temperature to tone down some of the hardness? And finally, should I have it rehardened when I am done? I do not want to end up with something that will blow up on me at a later time. Thanks for the help and advice.

[rjohns94]

I dont know the answers but the question is very interesting and I look forward to hearing what the experts say.

[J Miller]

I'm not a gunsmith, nor do I play one on the internet, but ....

Unless you are a skilled metallurgist with the proper equipment, or have access to one, I would not alter the heat treating on that receiver one iota.
The lines may be over polished, but as you said it's hard and probably should be left alone for safety sake.

Joe

[coyote nose]

Hi. I have a Chaparral 1876 and I LOVE mine the way it is...one of the prettiest guns I own. I guess you got one of the bad ones. Let me also add a disclaimer here...I am not a metallurgist or gunsmith either, but I do tinker with them and my profession is a tool and die maker in the automotive sector (at least until the lay-offs come!). We use 4140 pre-hard often where i work, but as stated it is in a prehardened state and the rockwell hardness is high, but not so high that a file wont cut it. we are able to mill it altho it is tough on tooling. When we need it real hard we have it heat treated after machining and then almost nothing will touch it. Used to do the hardening in the plant but lately with the layoffs at my plant we now send our hardening out of the shop. Thus when our heat treat guy was let go (incredibly smart and the one I would go to to get your question answered) I lost my source of info. I know one thing, I would be very very leary of several things contemplating what you want to do:
1. warpage with that large frame...I would worry about the tangs bending, or worse twisting like a propeller....may have to make up a fixture to try to hold everything straight. Even then the sides of the receiver, like where the carrier block rides, may slightly cave in which not only affects function but also appearance. Also the top of the frame whre the dust cover rides and the bolt rides inside would be susceptible to deformation.
2. some steels dont like being reheated and rehardened...dont know if 4140 is one of them (like I said...I am not a metalurgist).
3. a lower temperature (below red heat) would draw off the temper in the O-1 type steels, but warpage is still a factor and again I am not sure if 4140 benefits from this (see my disclaimer!).
4. If the receiver is designed to be hardened by the factory there is no way i would shoot one that is NOT hardened, and hardened to the rockwell the factory specified. Safety is the overriding issue, we are touching off a controlled explosion about 5" in front of our eyes.
Note the warpage factor is dealt with twice..once on the first heat and once with the reheat.
5. How do you know it is 4140?? Kind of curious
6. Abrasive paper WILL cut it. Have you considered getting some flat steel blocks and attaching black silicon carbide sand paper to it and using that to work the frame? Wet sand it. The stuff they sell at the auto store in various grades should do it. I would not remove much though and again, you are on your own as far as safety goes.
Hope this helps...You didnt ask but I will add my 2 cents as to what I personally would do with a gun that I didnt like the looks of the line of the receiver of...I would sell it. I like looking at my guns and any ugly ones are sold off. I'll take the loss of money over the loss of a finger, etc by messing with heat treating. I have done a lot of tinkering for my personal guns (relining, rebluing, fitting a new stock, making firing pins, etc), but re-heat treating a receiver is something that i just would definitely not do.

[Mike Hunter]

My first question is How do you know that the frame is 4140 series steel? Did you ask the importer and or Manufacturer?

Off the top of my head a file hardness made out of 1095 is around Rockwell 62-3, generally 4140 can be hardened to around Rockwell 56 or so. A file should still cut hardened 4140 steel, although a bit slowly, unless it’s been case hardened by induction hardening or cyanide.

4140 is a general purpose medium carbon steel, which is excellent for firearm frames… unless of course you want to color case harden them.

4140 is an oil hardening steel (hardened by quenching in oil) and a thru hardening steel (hardness goes completely thru the steel).

If it were me, and that frame is 4140 steel, I would not anneal it, I would use abrasive paper to polish the frame flat, then have it hot blued.

[Ben_Rumson]

Ditto on blocked abrasive paper.. Also stones..
FWIW I've got 4140 so hard that it took two months of 24/7 sand being pumped through it to erode it enough for it to wear through. An unhardened machinable piece lasted pretty close to a month.

[Ray Newman]

A now deceased very good friend ran the last heat treating shop-- Flame Treatment -- in Oakland, CA. If I recall, he was in the trade for 48 or 49 years.

During a conversation w/ John, I once asked him about heat treating receivers & how it is done. John explained that w/ unknown as well as known alloys, you never know exactly just how high the metal temperature reached w/o some very expensive & sophisticated equipment.

He also said if you heat treat (or attempt to) by watching the color change, you need a darkened room/work area & a very good eye for colors. Plus, it is a skill that is not learned over night.

When I asked him about retreating metals previously heat treated, he said there are two big unknowns: the exact metal composition & the quality of the previous heat treatment. He said a big issue w/ any heat treatment was not getting the metal too hot as it becomes brittle.

As Coyote Nose said warping is a big issue, not only w/ heat treating, but w/ colour case hardening as well. Often times, special jigs, blocks, etc., are utilized to prevent/reduce any warp.

Bottom Line: don't do it.

[kb466]

Thanks for the advice. The question was asked as to how I know it is 4140 steel-- I know this from contacting the importer and the manufacturer in Italy. Both said it is 4140 steel.

One alleged gunsmith emailed me and said that he thought that it might actually be stronger if somewhat annealed as 4140 remains strong but less brittle, thereby being more "ductile" and less prone to cracking or shattering. He also thought that an annealed 4140 receiver would not be a danger with 1876 loads as long as it uses black powder or equivilant. He said the receiver would retain sufficient strength for any stresses placed on it. He went on to say that the critical failure points in an 1876 are the toggles and the toggle pins. He says I should not mess with those. I do not know if he is well-informed on this issue.

Regardless, I am concerned about warpage. So, until I am convinced it will not warp and it will not do more harm than good, I will try working it with a file and various abrasives. If anyone else has any thoughts on this, please let me know.

[Buffboy]

Mike Hunter knows gun steels better than I do. It's good that you are not attempting to anneal your 76.

I've used 4140 for tooling and building of equipment when I was running a manufacturing concern. It's a good steel, fairly easy to machine and quite strong even without heat treating. It also has good abrasion resistance when hardened. It is also relatively easy to heat treat and is forgiving of slight errors. That said, annealing, then re-hardening or reheat treating any steel is problematic for someone without a furnace and sometimes even with (been there). An attempt to anneal your frame would likely not turn out well.

The "gunsmith" that emailed you is incorrect. The failure point of the 76 is not the links or the pins. Those are where the most wear will occur but not where the 76 usually fails in an overload. That point is usually the barrel/receiver at the point where they are joined. The 76 is a remarkably strong action. Far stronger than many give it credit for.

[kb466]

Thanks to all who responded. As I said and based on the responses, I have decided not to anneal it. I also just noticed that Mike Hunter was among those that responded. Having a great deal of respect for his opinion, I am going to go the route that he recommended. In fact, if this turns out well, or at least to the point I feel like I want to spend more money on it, I was planning on contacting Mike Hunter to do the remarking of the tang and barrel and bluing the receiver. I will do my own rust bluing of the barrel.

[Mike Hunter]

Thanks for informing us as to the steel used in the Chaparral 1876s. Friend of mine bought several of Chaparral‘s “rejects” , as a result I’ve ended up with a couple of the Chaparral 76 frames.

I was planning on truing up the frames and Color Case Hardening them, now that I know their made out of 4140, the Wood/Bone Color Case Hardening is not an option .

Thanks

Mike

Mike Hunter

[kb466]

Mike,
No doubt they are 4140. I heard it from the manufacturer and the importer. Later I noticed it on the Chaparral European website as well.

I am curious-- when you say you were going to "true them up", did you mean sharpening the lines and contours to correct the rounded, soft edges from over-buffing... or were you going to correct an alignment problem? Also, what materials were you going to use to "true them up"? I suppose I should say under-buffed because there seems to be sufficient material left to clean up the edges and lines when compared to an original-- at least on mine. Also, are there any issues with charcoal bluing a 4140 receiver? I understand that the receivers will get rather hot in this process.

If I can further pick your mind on this-- do you foresee any problems with remarking the "Model 1876" on the tang? I was also planning to have the too-long hammer opening welded up in the back and then filed or machined down to the correct size. I realize that welding on 4140 can be problematic unless the welder knows what he is doing. I was thinking that a Tig welder would be best for this kind of work as the heat would be more localized. I really appreciate the help. Thanks.
Bill Moyers
Santa Fe, NM

[Hobie]

You might want to retitle this topic "Refurbishing Chaparral 1876s".

Mike, I'd like to hear what you're doing as well. The thought crossed my mind that you might be producing "cat" rifles...

[kb466]

Good idea-- It has been done.
Bill M.

You might want to retitle this topic "Refurbishing Chaparral 1876s".

Mike, I'd like to hear what you're doing as well. The thought crossed my mind that you might be producing "cat" rifles...

[Hobie]

Mr. Hunter, what are your plans for those guns? Inquiring minds want to know.

I'm kinda stuck on the .45-75 now that I've got so much in brass,etc. but a 22" half-round or round barrel, button mag, shotgun butt, folding open sight and tang peep would seem to be a neat gun.

[Mike Hunter]

Hobie, What are “Cat Rifles”

Bill

Yes just clean up the lines, sharpen the edges. I was going to do what you were planning, anneal the frame, and clean up the edges on the surface grinder, possibly remark, then re CCH them.

That’s all out the window now that I know they are 4140 (I can’t re-CCH them).

Friend of mine bought a few of Chaparral’s “seconds” guns that had problems, importer found it cheaper to sell at big discount rather than return to factory.

He’s been stripping them, using some of the parts on Org 76’s, sends the BBLs to me to make the flats, flat again I re-roll them and he sells them as replacement shooter bbls.

I end up with the frames… he doesn’t want them.

I don’t see a big issue with charcoal bluing 4140 steel, charcoal bluing only gets to about 750 deg F. Welding is a different issue, after welding the area really needs to be annealed. Welding will cause hard spots and uneven bluing… generally annealing and or CCH will solve that issue, but it’s problematic now that we know its 4140 steel..see org post.

Roll marking the tang? … I see big problems, Hummm my roll die against hardened 4140 steel… I see die chipping and breakage… no thanks, roll dies are expensive.



Thanks

Mike

[Hobie]

Hobie, What are “Cat Rifles”

Mike,

Apparently the English bought a number of the 1876s in .50-95 configured with 24" round or half-round barrels, button-mags, express sights and shotgun butts for use on the large cats. Hence the term. The furniture was varnished rather than having the oil finish. I take it some actions (barrelled?) were sent to England and finished out there. There aren't a lot of them in this country. I imagine that they were used for more than just lions and tigers and leopards.

This rifle belongs to forum member Doc Cable...


And another from Merz Antique Firearms...

22” round barrel, button magazine, 85% lustrous barrel blue remaining, the balance turning plummish, considerable vivid case colors remain on frame, hammer and lever; generous amount of protective lacquer is present as well. Fine+ checkered deluxe pistol grip stocks retain most all original lacquer, original steel shotgun style buttplate, dustcover correctly marked ‘Winchester Express 50 Cal 95 grs’. Cody Research Form also mentions ‘Inside Finish’. $57,500

[Mike Hunter]

Ok now I get it; I’m fairly familiar with the British “Bush Guns” , I’ve had a few here in the shop. Many of the Mods were actually done in the UK or British territories.

Hummmm.. might be an interesting project, Heck I even have the british proof stamps

Mike

[Hobie]

I wish I had the money to do one right now. I was thinking of getting one of the 22" rifles from CDNN and reworking the configuration. Having handled the rifles, even my SRC is much handier.

[kb466]

Mike,
Thanks for the input. What are you planning to do with your frames now that you know that they are 4140? I am just trying to figure out what I can do with my frame in view of this information. I would still like to close up that hammer gap, but it sounds like it will need to be annealed if I weld on it. I wonder if rust-bluing will look different over the weld area? Anyway, do you have any suggestions as to how to recontour the frame, close up the hammer gap and refinish in view of all this? Any advice will be most appreciated.
Bill M.

Bill

Yes just clean up the lines, sharpen the edges. I was going to do what you were planning, anneal the frame, and clean up the edges on the surface grinder, possibly remark, then re CCH them.

That’s all out the window now that I know they are 4140 (I can’t re-CCH them).

Friend of mine bought a few of Chaparral’s “seconds” guns that had problems, importer found it cheaper to sell at big discount rather than return to factory.

He’s been stripping them, using some of the parts on Org 76’s, sends the BBLs to me to make the flats, flat again I re-roll them and he sells them as replacement shooter bbls.

I end up with the frames… he doesn’t want them.

I don’t see a big issue with charcoal bluing 4140 steel, charcoal bluing only gets to about 750 deg F. Welding is a different issue, after welding the area really needs to be annealed. Welding will cause hard spots and uneven bluing… generally annealing and or CCH will solve that issue, but it’s problematic now that we know its 4140 steel..see org post.

Roll marking the tang? … I see big problems, Hummm my roll die against hardened 4140 steel… I see die chipping and breakage… no thanks, roll dies are expensive.



Thanks

Mike

[Leverluver]

FWIW Turnbull did my Uberti 76. Came out looking pretty good to me. I didn't look heavily into the material though and Doug just went with what he was familiar with as far as other Ubertis such as the 73.

[Mike Hunter]

Right now they are just paper weights

Think I may anneal one then re CCH it just to see how it works out

Mike

[kb466]

Mike,
Well. if you do experiment with annealing, then CCH'ing one of them, please keep us informed as to how it turns out. Thanks.
Bill M.

[kb466]

By way of an update, I decided to go ahead and try some sharp files on my Chaparral 1876 action and was pleasantly surprised-- the steel was not as hard as I thought. It was hard, but the files did work. I have been draw filing it in places, removing metal to correct the contours and sharpen up and straighten the lines. There are a couple of places I had to remove quite a bit of metal to get it to point it was close to an original. I still have a lot of work to do, but it is really coming along. It is looking pretty good. I am not looking forward to the hand polishing, but I expect it will look good when it is all done.

Although I still believe it is 4140 steel, it is not as hard as it might have been-- good news as far as I am concerned. Oh, by the way, I have not annealed it and do not plan to do so.