New 642 38 +P

[Hemi Dude]

I recently bought a 642 38. The other day I tried inserting some 357 loads into the 642 to see how far they would stick out, and to my surprise they seated all the way down. Is this common on a 642? I always thought a 357 would not seat in a 38.

[Cooter Brown]

Just out of curiosity I tried that with my 642-- a 357 Mag. ctg. would not seat to the rim, by a pretty good margin.

I'm sure you know this, but DO NOT shoot any 357 ammo out of your 642.

[sgms]

Open her up and check you model number. Sounds like you may have a model 640, the .357 version of the model 642. Because you are right, the .357 mags. should not fit in a .38 spl.

[Hemi Dude]

Thanks for the suggestion I will check it out tonight.

[Maximumbob54]

All the J frames have magnum length cylinders but it would be a pretty big slip up to get a magnum milled out cylinder on a 642. The Airlites have near identical cylinders properly milled for magnums but I think they are heat treated and of a different alloy composition. And while I’m not sure how much scandium is in the alloy it is a very different alloy than the Airweights.

[Hemi Dude]

All the markings indicate a 642-2. Not sure what I have. Just tried a factory 357 and it seats to the rim.

[Maximumbob54]

Even if you feel comfortable I would still call S&W and arrange a replacement cylinder to be fitted. That is an accident waiting to happen. It may not be you but it's too risky to leave to chance.

[steamloco76]

Definitely call S&W! The huge pressure difference between +P .38 Special loads and .357 Magnum makes for an accident waiting to happen. If by some chance you have a 640 mislabeled as a 642, then S&W needs to document this, otherwise you have a 642 with a non-spec cylinder. Not good.

[Hemi Dude]

I will contact S&W and let you know what they say.

[Hemi Dude]

After talking With S&W Customer Service, I will be shipping the gun to them for a cylinder replacement. Thanks for all your comments and advise.