cap and ball revolver in .357 magnum?

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jason41987

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out of curiosity i was wondering if its possible for someone to convert a cap and ball, either an 1851, 1860, or remington 1858 to 357 magnum?.. i dont mean the removable cartridge conversions you see where you take the cylinder out, but im referring to the conversions ive seen where there is a cutout machines to the side of the frame and a loading gate installed, then a cylinder fitted to the frame with a fixed base pin

my question is, would there be enough cylinder length (im sure there is since they convert these to 45lc which has the same COAL), and enough strength in the frame itself to handle a .357 mag?... obviously both a cylinder and a barrel would need to be made...

looking at the .36 caliber cylinder, the ball is .375 diameter, almost identicle to the base diameter of the .357 magnum, it would need only a very slight work to make the chambers large enough, but im not sure if theres enough "meat" between the chambers to do this... so perhaps it would have to be a new cylinder on a .44 caliber frame?... and i do believe theres enough "meat" in the 1858 frame to do this, its atleast as sturdy as an 1873 colt frame and these handle .357 magnum all day... of course, id only consider such a conversion on a replica revolver made of modern metallurgy

so... doable?... and i know someone will just completely miss the point and tell me to buy a new double action revolver, or even an 1873.. but i like the looks of the old conversion revolvers between the civil war and 1870s and it would be nice to have the availability and versatility of .357 magnum ammo to go with it
 
In a word, no. Blackpowder pistols are not heat treated or proofed for such pressures. Colt percussion revolvers in particular would not withstand the backthrust of the .357Mag. Even though they are proofed for modern smokeless loads, the factory cartridge conversions also would not handle the pressure and backthrust. Which is why conversions on .36cal sixguns, factory or custom, are done to .38Colt or .38Spl. Even so, heeled bullets must be used for the .375" bore, or the bore must be relined to utilize modern inside lubed bullets. The factory conversions have the proper bore for modern inside lubed bullets. Either way, pressures must be kept relatively low.

The closest you're gonna get is the Colt SAA or Remington 1875/1890 replicas. Different animals entirely, with top straps and forged frames of modern steels.

www.cimarron-firearms.com/Specialty/1875Outlaw-Model1890.htm
 
If you have cubic dollars, you can DO anything. Whether it's WISE to do it, is another thing altogether. I'm thinking custom cylinder, barrel, possibly heat treating the frame. Less than 5k, more than 1k, but I doubt you'd find a reputable gunsmith willing to tackle it.

For a LOT less than such a conversion you could simply buy an 1875 Remington clone in 357 and have nearly the same look AND keep all your fingers intact.
 
you dont think the stainless, which is significantly harder than the steel they use in a lot of the replicas, wouldnt be a good start... i could probably machine the cylinder and lathe the barrel myself, but trying to determine what the end result woud be
 
Hardness has little to do with it. You're talking about manufacturers using alloys that are easy to machine. You can harden a part all day long but you can never change its composition. Nor will that make up for the inherent weakness in the Colt design. As a percussion gun or cartridge conversion chambered in a low pressure cartridge, it works fine. It's just not up to the pressure and backthrust. You can make a stronger cylinder but you can't make up for a standing breech that is only supported on one end. It simply was never designed to withstand forces of that nature. Think about the difference between ignition of a percussion cylinder and a cartridge bearing directly against the recoil shield. Very different.

Not just any machinist can produce a functioning cylinder from scratch.


If you have cubic dollars, you can DO anything.
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Only if you can find someone to take up your crazy project. I'm sure that with an unlimited budget, Dick Casull could whip you up one from scratch but then it wouldn't be a Colt or replica. Are you really willing to pay $10,000 or more for the privilege of shooting a .357Mag based on a percussion Colt.
 
+1 on what CraigC said above. I have seen the Colt design fail even with stout blackpowder loads. It is a very weak design. If you want a nice 357 magnum in a single action that will shoot heavy loads , look no further than the Freedom arms guns. Mine is the most accurate revolver I have.
 
Conversion revolvers are available in 38 Special, 44 Colt and 44 Special so I don't know why you want a 357 Magnum.

Substituting a cartridge cylinder does not change the overall strength of the gun and isn't a a good way to skirt firearm law for cartridge rounds.
 
The '75 Remington revolver was made to handle 44 WFC and .45 Colt, all was good; when repros became available in .357, it was found that their recoils shields were prone to being battered by the much higher-pressure rounds.

There are some conversions around for .38 Special, and folks like them, but every time I read someone's questions about turning their 1860 Army into a Raging Bull, I think of that song "Hot Rod Lincoln....."
 
you dont think the stainless, which is significantly harder than the steel they use in a lot of the replicas, wouldnt be a good start... i could probably machine the cylinder and lathe the barrel myself, but trying to determine what the end result woud be
Click to expand...

I suggest that you are operating under a few misconceptions.

First off stainless alloys used in firearms are not stronger than the classic regular steels used in handguns. At least not as a blanket statement. Each alloy from each maker would need to be compared. But it's a safe bet that the steel alloys used by the better replica makers in Italy would compare well with most of the regular stainless alloys used in making handguns.

The amount of work needed to produce such a gun would be staggering and hardly cost effective. Do you REALLY need an open top cartridge conversion that shoots full bore .357Mag's THAT badly?

A few things to consider off the top of my head;

  • It's not so much the cylinder that would be a problem but rather the main cylinder arbor and the wedge that holds it all together. That and the front heel of the frame and barrel is what will take much of the brunt of the energy. That and the threads in the frame that hold the arbor.
  • With the barrel wedge being in contact over such a small area the metal around that joint is going to need to special to withstand the pressures. Fourtunetly it would only be the residual that is seen at the head of the cartridge. But that's still like a pretty good whack from a hammer over and over and over....
 
i havent seen any .38 special conversions, but that would probably work out a lot better... however, 45lc and 44 special is not that common to find around here, not as much as you might think

is there a COAL issue with .38 special in a shortened cylinder for one of these revolvers? im not sure what the length of the cylinder front-to-back is, and if i recall the cylinders shortened to make room for the loading gate / firing pin assembly?... the one i seen had a frame mounted firing pin, so it was safe to carry hammer down as well, but i only found it in 45lc
 
.44Spl or .45Colt are the sort of ammo you want to reload anyway. What they charge for it is mostly criminal compared to the cost to reload these rounds. And the brass is available from a few places. Starline for one. Any outfit that carrys the stuff needed to support reloading for Cowboy Action shooters will have all the supplies you need to begin reloading for yourself.
 
Back in the early 1960s my wife's brother bought one of the early replicas of the Colt Army 1860, and loaded conical lead bullets with heavy loads of 3F black powder. After much shooting at a local black powder club the gun came apart and was destroyed. At that time the replicas were not as good as today. The "open-top" models offered by Cimarron in their conversion 1872 would be an excellent choice for you in 38 special , 44 special. Take a look at their web site.
 
i guess theres three ways i can go about this... first, authentic, by converting it to a cartridge available in this time frame between the purpose built cartridge revolvers and the cap and ball revolvers

second way i could go about it, is by converting to a common cartridge available shortly after in the time period where it was still cheaper for a lot of people to convert older revolvers as opposed to purchasing an 1873 colt or 1875 remington, these cartridges would be .45lc, .44wcf, .38-40, .32-20, etc

and the third way is using a late 19th century to modern cartridge that could be made to rival the performances of these older ones, but be more available today, like .44 special and .38 special

would there be any noticable size and weight disadvantage to the 44 calibers vs the 36 calibers?.. i get the impression the .36 calibers were considerably smaller, lighter than the 44s, and would a 36 caliber colt be a good candidate to convert to 38 special, or am i really better off looking at 44 caliber models?
 
It would help if you would explain why and what you are trying to do with converting a B/P handgun to smokeless cartridge.

The bore of a 36 caliber C&B is oversize for the .357 sized bullet. The originals used a heel type bullets to fit the bore.

A factory made Uberti Conversion handgun will have the correct size bore for use with modern bullets and cartridges.

You will probably get better advice from folks that shoot these guns all the time at;

http://sassnet.com/forums/index.php?showforum=12
 
i guess another question is... out of uberti, pietta, and various other manufacturers, who actually makes the highest quality replicas? any american companies making them?

BSA1, i was looking for a project to do over the winter... a machining project, and converting a cap and ball revolver wouldnt be a bad place to start.. if i mess up, im only out a cheap black powder revolver
 
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The cylinder isn't the limiting factor in a cartridge conversion, it is the frame. An open-topped frame, as found on all the Colt cap & balls, is not going to hold up to even standard .38 Special pressures, let alone .357 Magnum. I doubt if the Remington, though it has a closed-top frame, is going to do much better. Buy a Colt SAA or Ruger in .357 Magnum if you want the magnum power.
 
Well, .38Spl should be OK since Uberti already makes a .38Spl open top "conversion". But yeah, to expect it to withstand .357Mag seems out there. If it were possible I expect you'd be looking at a whole new gun from the frame to the cylinder arbor to the barrel metal and even the barrel wedge would all need to be made from some pretty fancy alloy and heat treated to achieve the strength and toughness.
 
You could convert an 1860 to the modern version of .44 Colt.
The original had a typical 1870s outside lubricated heel bullet, big enough for the .44 bore = .45 groove barrel of the percussion guns.

The modern version is the same OD as a .44 Special with case length intermediate between Russian and Special and reduced rim diameter. It is meant to be loaded with a modern .429" bullet, so you would have to line the barrel to handle that.

Modifying the cylinder and machining a conversion ring will add to the fun of the project.
You may have to do some action work, too.

Of course that gets you away from your original idea of a cheap powerful gun on the weak old action, but it has the advantage of being possible and safe.

Or just go from .36 to .38 Special.

I have one of the 1970s Legal Defender .38 S&W cylinders in a .36 Navy with barrel lined down to .358". Cute. Not powerful, though.
 
I'm sorry but a cartridge conversion isn't something you just build one day because you're bored. Particularly if you don't know any more about it than you seem to. That said, Bruce McDowell's book on Colt cartridge conversions has all the technical data you'll need. Bear in mind that you'll also have to construct a conversion ring with a floating firing pin. To be done correctly, you'd probably spend all winter just planning.

Or you could just buy one. :rolleyes:


im aware a new barrel would be needed to do it properly
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It would be too complex to machine a new barrel and it's not necessary anyway. What you would have to do is reline the barrel.


An open-topped frame, as found on all the Colt cap & balls, is not going to hold up to even standard .38 Special pressures...
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They hold up just fine to .38Spl pressures. Otherwise they wouldn't be built in the chambering.
 
Too many people forget that, when it comes to 19th century firearms, modern reproductions may employ better steel, but it is the DESIGN that is weak point.
Precisely why a reproduction 1873 or 1876 Winchester remains relatively weak, compared to the 1892: design.
It's why the reproduction 1873 Springfield "trapdoor" .45-70 should not be loaded to a higher pressure than an original Springfield in good shape: design.
The Colt and Remington cap and ball revolvers were plenty strong in their day, when black powder was the only propellant. But after smokeless powder appeared, people began stoking them with this new powder and blowing them.
It can still be done today, with a new reproduction.
The convertible cylinders may be heat treated, but their manufacturers don't encourage anything but mild loads: no +P loads or anything approaching those pressures.
And you ponder rechambering a .38 Special cylinder to .357 Magnum?
That's a leap from about 12,000 Copper Units of Pressure to about 40,000 CUP. This tell you why it's not recommended?
 
I'd never try to convert one but I would LOVE if it were some feasible way to make an 1851 or 1860 into a 357 magnum. Doesn't sound possible with the lack of a top strap but it would be nice. There is simply no beating the ergonomics of those revolvers.

How about the modern conversions? Will they handle standard pressure 44 special or 45 colt loadings in smokeless?
 
shafter said:
I'd never try to convert one but I would LOVE if it were some feasible way to make an 1851 or 1860 into a 357 magnum. Doesn't sound possible with the lack of a top strap but it would be nice. There is simply no beating the ergonomics of those revolvers.

How about the modern conversions? Will they handle standard pressure 44 special or 45 colt loadings in smokeless?
Click to expand...
The ITalian copies need to be proofed before they can be sold, so they will withstand "standard"loadings. I have a Richards conversion of the 1860, chambered for the 44 Colt, and reload for it. I use blackpowder and lead, nothing fancy but it works.
 
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