Sorry I have not been on in a while. The gun is a .38 spcl. only. It will handle .38spcl. +p without any trouble. The guns that chamber .357 Mag will take both .357 Mag, and .38spcl. though if you shoot a lot of .38 spcl it will make chambering .357 mag difficult in some guns due to a build up of carbon. A cleaning will usualy clear that up. I am a beliver in .38spcl+p is nothing to sneeze at. It is easy for most beginners to shoot from a medium framed revolver without getting thier hand beaten up, and them developing a flinch.
The only real advantage I know of is there is less of a flash from unburned powder from .38 spcl, and not nearly as loud of a report from the shot. I own a couple of other .357 mag guns. I shoot .38 spcl almost exclusively even though I hand load.