Model 67 convert to 357 mag?

[rosewood]

I feel exactly the same way about cylinders.

It defies modern mass production for S&W to have different processes in place for K-frame .38 Special cylinders and K-frame .357 Mag cylinders.

The very suggestion or idea of this slows production.

My thought exactly, now before they started making them in 357 mag, maybe so, but once the mag was in production in that frame, it would make the most sense to make them all the same to the required specs for the worst case scenario.

Rosewood

 

[rosewood]

I wouldn't worry about the frame. I would have a small degree of concern about the cylinder. I find it hard to believe any modern frame received a inferior HT when it would be no more trouble or cost to HT them all the same. But that aside consider the model 360 scandium alloy J frame 357s. They are built on a smaller, lighter, frame of scandium alloy which has a tensile strength of 350 MPa and the yield strength of about 280 MPa. Where 4140 steel has a tensile strength of 655MPa and a yield strength of 415MPa straight from the mill. In other words a NON heat treated 4140 frame is almost twice as strong as any scandium frame. Same applies to the N frame alloy guns. I have J, L and N frame scandium guns. They are dimensionally the same as my steel ones. Where are the blown up scandium frames??? Obviously the frames do not need nearly the strength of 4140.

Top strap? While they are a great addition and necessary with modern rounds look at the construction of the fairly powerful Colt dragoon. It could fire a 144 gr 44 caliber ball at 1200fps and didn't even have a top strap, and the barrel was held to the frame with a wedge. .

BTW on Titanium you have to go to the highest grade (and cost) alloys to achieve the same tensile and yield strength as 4140

More than one K 38 cylinder has been reamed to 357 and not blown up. Plus quite a few 38 cylinders have been reamed and cut to fire 9mm which are about the same pressure as 357 and end up with less metal at the stop notch from the reaming. Where are the blown up guns or even the reports of them???

But, model 19, 13 and their stainless counterparts are not hard to come by. It is also not hard to face off the barrel extension and recut the forcing cone on a 38 special revolver so one fits.

It is even easier and unless you have your own shop and skills less expensive to just trade your 38 on a 357 or buy one.

I have 2 38 cylinders I reamed and cut to 9mm which I have fired repeatedly, but only because I chose to have a a gun that could fire 9mms.

I also reamed one K38 cylinder to 357 and fired some 357 rounds though it. I did that some time ago, but decided it was better to go with factory 357 cylinders so it sits in my parts pile another experiment.

Now this makes sense. Using actual numbers and specs instead of speculation.

Rosewood

 

[glenwolde]

I feel exactly the same way about cylinders.

It defies modern mass production for S&W to have different processes in place for K-frame .38 Special cylinders and K-frame .357 Mag cylinders.

The very suggestion or idea of this slows production.

I don't see how it slows production, if it's a step that's eliminated.

Let's say you can heat treat 100 cylinders a day. Why heat-treat .38 cylinders? You've limited your .357 production by however many .38's you're doing which raises the unit cost of the .357 cylinders. You've also delayed the .38 production by the amount of time the heat treatment takes.

Not to mention that nothing is free. Heat treatment is then a cost that's now added to the .38 cylinders.

If they are heat treated after machining the .38's and .357's are already sorted so there's no added cost for sorting. If they are machined after heat treating there's the extra wear on machine tools from the unnecessarily hardened steel of the .38 cylinders.

It may not be much more expensive to just do them all, but it for sure is not cheaper or faster in my view if you look at it from the perspective of the production time and cost for the two calibers individually.

 

[steelslaver]

If you heat treat the cylinders post machining you will have some degree of dimensional shift. Heat treating reforms the shape of the steel's internal structures which effects their shape. If I took a perfect cube or sphere of 4140 hardened it and then tempered it, it would not longer be a perfect cube or sphere. If i drill and ream say a .250 hole in a piece of tool steel then harden and temper it, a .250 pin gauge will not go in the hole post HT. Been there done that. Exact same thing would happen to a cylinder. There is absolutely no reason than the cylinder material could not be HT as long lengths of round stock. Then there is no need to track which got treated and which did not PLUS, a big drop in liability. If a 38 cylinder blew up for any reason it would be possible for S&W to be held liable for failing to use best possible method to insure safety.

The wear on additional machinery would be near zero as it is not at all about hardness. I have a hardness tester checked some frames and both 38 and 357 cylinders and they are the same hardness are the frames. In fact after checking them in Rockwell C scale I went to B scale to get more accurate readings because they were all so soft, in fact around 102-4 Rockwell B. Which is around Rockwell C26 and not very hard at all. Mild steel is softer but not by that much. A poor knife soft blade would be RC56.

It is NOT about hardness with cylinders and frames it is about tensile strength and yield strength. A fully harden cylinder would be a shrapnel bomb

I actually studied metallurgy, Heat Treating and even have my own oven.

 

[Pine_Worker]

Instead of modifying a 38 Special revolver, trying to turn it into a 357 Magnum, why not sell/trade it and buy a 357 Magnum revolver?

What ^^^ said.

 

[BobK]

The 67 is a pleasant gun to shoot.......with .38 Spl +P ammo, which I shoot in all my .38 Spl. guns, and in my M-66-1 2 1/2" .357. It's plenty strong enough for me, and not as expensive as .357.

The frame and forcing cone was made to shoot .38's, and using .357 ammo constantly in it can cause excessive wear, and cracks in the frame. S&W recommends using .38 Spl. in the 66, mostly......357 only occasionally. BobK