K frame from .38 special to .357M

[gunnie]

i have been told it is not safe to rebore a .38 special K frame smith and wesson cylinder to .357M due to the higher SAAMI pressure rating of the later.

not having both in hand, i think the K frame 357 and 38 cylinders are equal diameter and chamber wall thickness. i also think a K frame has the same dimensions and metal thickness inside and out from OEM S&W offerings in either caliber.

i am not sure about overall cylinder length, but same could be accommodated for by shortening the forcing cone/bbl extension inside the frame's cylinder opening.

can any of you offer up hard copy proof, not speculation, that this is true/untrue?

i have the speculation part covered already.

thanks in advance,

gunnie

 

[absolute0]

Gunnie,

In addition to being slightly dimensionally different in some areas, K Frames chambered for .357 also receive some extra metallurigcal magic (heat treat) to help deal with the higher pressures generated by the .357 magnum round.

Buy a model 19 or model 13 and be happy

 

[rcmodel]

Bad idea.

Not all S&W's were created equal in the steel grade and heat treating department.
And they ain't exactly telling which ones were and which ones weren't.

The .38 cylinder is only 1.560" long.
The .357 SAAMI spec OAL is 1.590".
The K Mag cylinder is 1.670" long.

Shortening the forcing cone / barrel shank cannot be done without making the cylinder longer to make up the difference.
And thats a fact.

rc

 

[SaxonPig]

#33

Modifying a gun into a different configuration.

33. Trying to turn the gun you have into the gun you want is never a good idea. It will be cheaper, faster and easier to sell the gun you don’t want and buy the one you do want rather than try to alter or convert your gun into a different configuration. In most cases the alterations suggested are not possible to due to physical limitations and if they were the cost of such work would be beyond all but wealthy fools who like to throw their money away.


Note: I would add that in this case the cylinder will likely be too short. Also as someone said the Magnums got better tempering. If you want a K frame 357 then buy one.

 

[earlthegoat2]

I need a list of these rules SaxonPig.

Has some gun rag run an article on converting guns lately or something because there seems to be lots of threads on it recently and only bad gunwriting could have caused it I think.

 

[BCRider]

NAH ! ! ! He's making them up as he goes along.... He's as bad as that Confucious guy

He's 100% right though. The cost of that level of custom work or even anything close to that level would far and away exceed the cost of selling and buying the new format.

Gunnie, your project is doomed from the start by the extra length of the .357 round. They sized the Magnum case longer to prevent folks from doing exactly what you're suggesting for all the good safety reasons mentioned already. Don't try to do any sort of work around.

 

[SaxonPig]

Actually, it's a list of 100 answers to FAQs on firearm discussion forums. But I'm only up to #69 so far. I have written answers for questions that seem to come up over and over again.

Here's #6 just for another example.

Hollywood guns.

6. When asking what kind of gun was used in a movie or TV program always remember that it very possibly could have been a gun made up by the prop department rather than an actual gun and that’s why you may not be able to recognize it.

 

[Blue Brick]

This can only be done to a Ruger 38 Spl.

 

[earlthegoat2]

Can I get a link?

 

[BCRider]

Hollywood guns.

6. When asking what kind of gun was used in a movie or TV program always remember that it very possibly could have been a gun made up by the prop department rather than an actual gun and that’s why you may not be able to recognize it.

So... you're sayng I should give up my quest to find my own revolver like the one used by Hellboy? NEVER ! ! ! ! ! S&W 500 BE DAMNED! I WANT MY 20MMSHORT CANNON SHELL REVOLVER ! ! ! ! !

Hmmmm... so you ARE making them up. Just not as you go along. I look forward to seeing the final published version. Should be a lot of truisms in there. It'll really shorten up the replies too. We'll be able to just type "#54" or "#'s 36 and 81 apply here". And occasionally someone will reply with "#49" and the next 5 replies will be "LOL PWNED"....

 

[SGW42]

I always thought the "Achilles Heel" of the K-frame .357 Mags was the large forcing cone that had to be "trimmed" to accommodate the ejector rod. Hence the L-frame.

(The flat part at the bottom of the cone in this pic of my 19.)


In fact I was told to take it easy on .357 Mags out of my 19. I only shoot a cylinder or two of them per range session, 158 grn ones at that.

 

[BCRider]

I've seen info that says to do that and a couple of folks (Chuck something with the big website is one) that say they've shot almost nothing BUT Magnums through their 19's with no ill effects.

But given the idea that where there's smoke there's fire I tend to shoot far more .38's than Mag's through mine. Although a fun thing to do is play Revolver Roulette. Load five .38's and one .357. Give 'er a spin then without looking stop the cylinder and close it. Does wonders for checking to see if you still have any flinch issues....

 

[Brian Williams]

This is done, Do not up fit a S&W K frame in 38 Special to 357 mag.