Quote Originally Posted by Alex_C View Post
The cylinders are also slightly different shapes. Not sure if this has anything to do with the higher pressures of the magnum round or not.

In any case, I would NEVER fire .357 out of a revolver rated for .38 spl.
The chamber on the .38 is shorter and you wouldn't be able to close the cylinder with .357 ammo in it.

There is actually enough capacity in a .38 Special case to get magnum velocity and pressure if you so desired. The extra length of the .357 was purpose designed to prevent it being loaded into a .38.