revolver cylinder heat treatment

[frontloader]

Hi all , been lurking and learning.but cant find a answer. is it possible to re-heat treat a factory .45lc 4140 CNC machined steel revolver cylinder to withstand greater pressure? If so who could or would do it? The reason I ask I really like the 1858 Remington revolver, and with the conversion cylinders on the market all you can safely shoot are cowboy loads. I want to use this revolver for deer hunting and safely shoot a 250 gr bullet about 1200 fps. No I dont want a blackhawk. and yes I know a cowboy load will kill deer.Hartford Armory made a few then stopped a while back. USFA said they were going to make one also.didnt happen....Thank you.....frontloader

 

[Alpacca Fortyfive]

My W A'd guess is no.

Here's why.

If the existing cylinders are heat treated 4140 and they won't take the loads you are looking for, you need to ask the question of:

why their manufacturers went to the expense and trouble of machining them from a high strength and therefore hard(ish) on tools steel then heat treating them to a less than optimal level rather than use a cheaper free-er machining steel?

my guess is that they did heat treat them to the optimal balance of tensile strength and toughness, and that the problem you are facing is the wall thickness of the chambers is not sufficient to hold the pressures which you want to use.

The solution to that is a gun with a larger diameter cylinder.

 

[frontloader]

Thanks Alpacca fortyfive.The cylinder in question is 5 shot[plenty of meat between chambers] R&D .45lc conversion .as far as optimal strength and toughness,I think they stopped at SAAMI pressures of 14,000 psi + their saftey factor.we have a member here david n I belive that works with Kirst conversions.I hope he will chime in.

 

[ahall]

Even with a 5 shot cylinder, the OD of the cylinder remains the same, so you run into a fundimental limit on wall thickness.

Cylinder is probably made from bar that is heat treated, then machined. The tolerances on chambers and indexing notches are tight enough that heat treating after machining will create a lot of parts that walk around and wind up out of tolerance. Yes you get some dimensional changes in heat treating. Not all are predictable. Also, the more changes in cross section you deal with in a part, the more likely it is to crack when heat treated.

So, the upper limit on material strenght is probably based on the need to machine after heat treating, not the upper limit the part can be heat treated to. None the less, reheat treating is asking for problems. Parts dont like it.

If the pros are not willing to take on the liablity, perhaps you should take a hint.

A while back I ran throught the thick wall cylinder equations and looked at the necessary wall thickness to use a 44 special in a black powder conversion and was uncomfortable with the results, ever with the steel I have access to make the cylinder from. I will stick to 38's.

 

[shunka]

Not a good idea

Greetings -
I correspond sporadically with the gentlemen involved at Kirst. I can safely say on their behalf "stick to the cowboy loads" and for the following reasons:

The 5 shot Kirst cylinder is quite strong- probably considerably stronger than the replica Remington revolver. Thus the limiting factor is in fact the revolver.

You will find the replica Remington frame is smaller than the Colt 1873 frame, and is specifically designed for the BP loads that the BP cylinder will handle, plus some safety factor (they are after all proofed in the EU by law). They also use lesser strength, softer (ie cheaper ) steels in the BP revolvers vs the cartridge revolvers.

And even then, the Colt 1873 frame is not stout enough to handle the load you are contemplating.

Thus it is not the cylinder strength you should be concerned with, but the frame strength.


If you really want 1200 fps loads with a 250 gr bullet you are literally looking at .44 magnum specs, or the "Ruger Only" .45 Long Colt loads. These Loads can be managed in the large, heavy frames like Rugers, Virginia Dragoons, etc.

Personally I would not even trust a repro Colt Dragoon or Walker with such loads.

The only BP revolver that one might "load up" close to that using a conversion cylinder would be the Ruger Old Army, which is out of production but available used at $450 and up.

hope this helps
shunka

 

[huntinguy]

shunka is dead on.

I had a very similar conversation with Smith and Wesson last year about rechambering a revolver. The issue was frame strength not cylinder strength.

 

[david n]

The 5 shot Kirst cylinder is quite strong- probably considerably stronger than the replica Remington revolver. Thus the limiting factor is in fact the revolver...................

.....................Thus it is not the cylinder strength you should be concerned with, but the frame strength.

He said it all right there.

You might (and that is a huge MIGHT) get by with a Ruger, but it was still designed and mfg'd as a BP pistol. R&D and Kirst RECOMMEND ONLY COWBOY LOADS!!!!!!!!!!!!! Go out and buy yourself a modern revolver if you need to shoot hot/mag loads to hunt deer.

I've seen the destructive forces of hot Long Colt loads in BP framed revolvers. IT IS NOT WORTH THE RISK!!!!!!!!!!!

 

[jabezkin]

I'll go with David N.
I've built a lot of high end cylinders. And to bet your eyesight or life against the price of a beater Blackhawk based on a SWAG is beyond me.