J frame 38/357 cylinders

[Robert B]

Am I right that J frame cylinders for 38+P are 357 length due to the use of the J magnum frame to allow for extra frame material for 38+P revolvers?

[HAWKEYE10]

A 357 mag. bullet is to long to fit in any gun that is
designed to shoot a 38 SPL. or 38+P only. Don

[DrewW]

First let me say that I don't own any J-frames but here is my take on your question and possibly someone who has both can come along and agree or call me a liar.

Anyway, to answer your question no a 38+p cylinder is not the same length as the .357 Mag cylinder. Both guns do use the magnum frame however with the longer window to allow for a .357 cylinder.

The barrel on the 38+p gun is just set back farther in the window to make up the difference.

[WC145]

The newer "magnum" frames and cylinders are all the same dimensions, it's cheaper to make just one size. They don't use shorter cylinders with the barrels set back for .38's, they use magnum length cylinders cut for .38 cases.
.357mag cases won't fit, they're too long for the headspacing in the .38 cylinder.

[DrewW]

Thanks for clearing that up WC, I wasn't sure how exactly that worked now I know.

[Robert B]

can you clarify what you mean for "cut for 38 cases" and what is headspacing?

[valkyriekl]

headspacing == how a cartridge seats in the chamber. Rimmed handgun cartridges, usually intended for revolvers, will "headspace" (or be fully seated) on the rim. Un-rimmed handgun cartridges, usually intended for autoloaders, will headspace on the case mouth.

The chambers in a revolver that are cut for .38 Specials have a step near the case mouth to center the bullet (which is actually .357" in diameter) before it leaves the chamber/cylinder and enters the forcing cone and the barrel. This "step" in the chamber is a certain length away from the breech.

For .357 Magnum chambers, this step is a bit further away, since .357 Magnum cases are a little longer than .38 Special cases to prevent them from being used in (and blowing up) guns that were chambered for .38 Special only. Thus, .357 Magnum cases will not headspace correctly in .38 Special chambers.

[pittpa]

About 1981 Colt started selling the Python 38 Target, created from a 357 revolver by drilling the chambers so they would fit a 38 round and not a 357. The cylinder and the frame are the same dimensions as the 357 version. Pretty much exactly what you are talking about here.