Does anyone know if it is possible to convert a modern/current .38+p rated J frame to .357?


At first glance this may seem like a stupid question, since .357 has so much higher pressures,  but after thinking about it for a bit,  I am not sure.

As best I understand it, all current J-frame's are made on a "magnum" frame that is slightly longer than the older J frame,  and there are .357's made on this frame in both steel and scandium, and as far as I know the same magnum frame is used for all pistols (.357's, .38's. and .22s).

Does anyone know for sure if that is true?  If so, it would suggest that the frame is fine for .357's, which would leave the cylinder as the potential weak link.

It certainly seems possible that they might do a different heat treat or something on the .357 cylinders.   However, the fact that Pinnacle (http://pinnaclehighperformance.com/cylinder-work/) appears to rechamber .38 j-frames to 9mm which operates at the same pressure as .357 suggests that maybe even the .38 cylinders are the same strength as the .357 cylinders,  just with a shorter chamber?


The obvious solution is to just by a .357 J frame from the factory and not worry about it;  however, I really like the idea of a model 638 (shrouded hammer, not the fully concealed hammer) in .357.  There seem to not be very many 638's floating around, and I have never seen one in .357....  So that got me idly thinking about the feasibility of building one!

Let me know if any of you have any experience or thoughts on the subject,  Thanks!

I have a Smith 342PD Airlite Titanium .38 Special pistol I carry sometimes. I load it with Corbon 110 grain +P hollowpoints as a compromise to carrying a .357 Magnum.

How many 357 or 38+P rounds have you shot in an alloy J frame?

You could not pay me to shoot 357 in one.  

IMO, your shots will be more accurate and faster with 38 Special, and only hits count.

Can it be done? Yes. It's simple as reaming the chamber to .357 length.

Can it be done in a 638? Yes. Should it be? Absolutely not.


Smith and Wesson does not make an airweight .357 J-Frame. Aluminum frames simply won't stand up to .357 Magnum, you might get 10 shots off and crack the frame, you might 1000, you might get 1. If you want to do this, you'll want either a steel or Scandium framed revolver.


As was mentioned, in a J-frame snubby barrel, you receive just about 0 benefits over .38 Special. You're already extremely limited in capacity, so it's vitality more important to actually get hits, than create huge fireballs.


My opinion, takes this idea and put it down like a rabid dog behind the woodshed.

double tap

Steel frames can probably be converted.  Aluminum frames almost certainly not.  Scandium frame (just an Aluminum alloy with ~0.5% Scandium) could but I don't believe S&W makes a 38 Special Scandium frame.  The Scandium frames are all 357 Mag.  But I agree if you want 357 Mag buy a 357 Mag.  You will have nearly as much money in a 38 Special and the conversion as you would if you just bought the 357 Mag in the first place.

Strictly ballistically speaking 357 Magnum (@35,000psi) is significantly more cartridge than 38 Special +P (20,000psi) even when both are fired from short 1-7/8 or 2 inch barrels.  Now does that extra velocity result in a more effective self defense gun, does it offset the down side of recoil and muzzle blast?  That is arguable but there is not doubt 357 Magnum is a lot more cartridge that 38 Special +P when compared in any barrel length.