Model 10 in 357.

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Barry loyd

Barry loyd

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BF8C56AF-A4B5-4EA6-A524-A939D3A029A1.jpeg 429C0A29-7489-49B8-A732-268CDFC82390.jpeg Warning ⚠️. Do not try this yourself. This is not an endorsement of doing this and I am in no way saying you can do but only that I did it. I will not go into detail as to how I did it.

With that out of the way I’ll get to it. I took MY model 10-6 heavy barrel and bored the cylinder to accept 357. There are some that say it can’t be done safely that the heat treating for 38 and 357 are different and there are those that say all the heat treatment was the same. I subscribe to the latter. I plan on keeping the loads relegated to 158gr loads. Hodgdon’s starting load with H110 is 28,600psi which is low for 357. Before anyone says “just get a 357” I have a 686+. I wanted to do it just to do it. So far after 25 rounds it’s holding up.
 
Obturation said:
Why? Wouldn't it be the same thing to just load the 38 sp heavy? I was under the impression the main reason for the longer 357 case was to prevent putting the cartridge into a shorter chamber - not really needed to hold more powder.
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Shorter case= higher pressure. I could load 38 hotter but like I said, I did it just to do it.
 
I know a very reputable gunsmith that bored many model 10's for LEO's in the 70's and 80's. Department Regs said 38 spl only but most were carrying .357 Loads in their Model 10. Same gun as a model 13 with a slightly different length cylinder. I owned one of his "conversions" for years. Never had the slightest of problems.
 
Barry loyd said:
View attachment 880280 View attachment 880281 Warning ⚠️. Do not try this yourself. This is not an endorsement of doing this and I am in no way saying you can do but only that I did it. I will not go into detail as to how I did it.

With that out of the way I’ll get to it. I took MY model 10-6 heavy barrel and bored the cylinder to accept 357. There are some that say it can’t be done safely that the heat treating for 38 and 357 are different and there are those that say all the heat treatment was the same. I subscribe to the latter. I plan on keeping the loads relegated to 158gr loads. Hodgdon’s starting load with H110 is 28,600psi which is low for 357. Before anyone says “just get a 357” I have a 686+. I wanted to do it just to do it. So far after 25 rounds it’s holding up.
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I do NOT want to know when [ NOT IF ] this ends in the ruination of your face,hands,others in your AO.

If you have any clue as to the C.U.P. of the .38 smith & Wesson special,v/s the C.U.P. of the .357 magnum = and you persist at this,sorry but put me on your insurance PLEASE.

And if you don't know what C.U.P. means,your really playing with a match that will light you up.
 
MosinT53Hunter said:
Best also if you were to sell it down the road, mark the pistol in some way to show what modifications you did to the gun. Just my two cents.
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I don't see that as an issue. Future owner would use ammo as marked on the barrel which in theory should still be fine depending on what exactly has been done to it
 
I would do it with my 10-6 and have seriously considered it. I think my gun will go a different direction though, 32 caliber, just not sure which flavor. K-32s are stupid expensive, but a 32-20 barrel and a bored 22lr k frame cylinder will do the trick. I do have concerns about timing it, but that’s just another challenge to have fun overcoming. I’m leaning towards 32 mag, I would not want to jump all the way up to .327fm levels.
 
scaatylobo said:
I do NOT want to know when [ NOT IF ] this ends in the ruination of your face,hands,others in your AO.

If you have any clue as to the C.U.P. of the .38 smith & Wesson special,v/s the C.U.P. of the .357 magnum = and you persist at this,sorry but put me on your insurance PLEASE.

And if you don't know what C.U.P. means,your really playing with a match that will light you up.
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I wouldn't necessarily advise it as S&W claims the 3200 10-6 HB .357 Mag cylinders had a different heat treat than than the 10-6 HB .38 Special. That said this was done many times in the past and the one issue most seemed to have was any bullet creep tended to tie up the gun. Assuming you didn't shorten the forcing come and install a Model 13 Cylinder which would make the revolver essentially a Model 13.

Really given the price of a Model 13 it seems to make more sense to simply get a 13.
 
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why not just swap to a .357 cylinder? didn't they make a k frame .357? I guess if you just wanted to see if you could do it and if it would work, nicely done. seems a little risky, not that is all bad - but, the boring police will give you a hard time I'm sure
 
Obturation said:
I don't see that as an issue. Future owner would use ammo as marked on the barrel which in theory should still be fine depending on what exactly has been done to it
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I would agree the future owner "should" use ammo as marked on barrel but that doesn't mean he "would" whether intentionally or not. Non-issue if OP doesn't pass it on. Nice work, OP!
 
Isn’t this asking to shoot that gun loose early?

I guess I just think there’s a lot of good 357’s out there so forcing something to be what it isn’t is just going to beat the gun up. But we all have hobbies I guess.

Stay safe.
 
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If treated like many of the remaining 357 K frames, loaded somewhere between 38+P and low end magnums it should live a very long life.

Should being the operative word.

I don't think it'd blow up, maybe go out of time or something else non-catastrophic if anything.

Think being the operative word.

I wouldn't mind doing it to my own gun if I didn't already have a couple M19's.
 
I remember the old gunwriter Jan Liborel wrote and article about a trip he made through the S&W factory and he stated the 38 and 357 cylinders all got the same heat treatment. He even had a photo of the cylinders in the rack that was loaded into the oven.

But I would just stick to low end magnum loads at the most. The same loads you could have gotten with 38 Special brass and duplicate 33/44 loads that lead to the invention of the 357 round. I load a lot of those type loads myself. Any where from 6.6grs to around 7.5grs of Unique or any similar burn rate powder. I also like 8grs of Blue dot in a 357 case all with 158gr bullets. About the lightest bullets I like are around 140grs.

This was a good thread on mid range 357 loads.

https://www.thehighroad.org/index.php?threads/whats-your-favorite-mild-to-medium-357-load.858676/
 
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460Shooter said:
Isn’t this asking to shoot that gun loose early?

I guess I just think there’s a lot of good 357’s out there so forcing something to be what it isn’t is just going to beat the gun up. But we all have hobbies I guess.

Stay safe.
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Wouldnt shoot loose any faster than the Model 19s, which have the same guts.

Really, the only issue I see is if the heat treatment was in fact different for the Magnum cylinders. Since it would require seperate processes and be more costly to do them differently, I subscribe to the theory that the metallurgy is the likely the same.

That said, all vintage K-frames are a bit too lightly built for shooting Magnums anyway, IMO. I do like the OPs conversion, though, as it gives it an added capability to fire the longer ammo in an emergency.

Kinda like shooting .32acp in a .32 S&W.....not a great idea, but you could if you HAD to.
 
film495 said:
why not just swap to a .357 cylinder? didn't they make a k frame .357? I guess if you just wanted to see if you could do it and if it would work, nicely done. seems a little risky, not that is all bad - but, the boring police will give you a hard time I'm sure
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To swap in a longer cylinder, you would have to shorten the barrel extension and recut the forcing cone.
 
Technically, the .357 was only introduced so that very hot .38spl factory loads could be marketed, which would run the risk of blowing up some of the early .38 special designs. Far easier to make a tad larger chambering that’s not interchangeable, than to risk injuries and lawsuits.

In theory, therefore, there’s nothing at all wrong with rechambering a stout .38 revolver.
 
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