I'd like to know that answer. I used to think that they were identical (except for chambers), as it didn't make much sense to me for them to heat treat identical cylinders differently, unless there was some greater cost to the magnum heat treatment. To do them differently would mean that S&W 'engineered down' each gun to the ammo for that gun.

For example, is the K frame .32 intentionally engineered to be 'weaker' than the K frame .38? How about the .22 K frames? I know that sounds silly, but if that is not the case then it would seem the .38's could handle .357 loads. What do y'all think?