Is there a significant difference in .38+p amd .357 mag?
Certainly in the recoil and flash in a small revolver, there is a significant difference. I just recommend getting the LCR/SP101/J-frame chambered in .357 because you always have the option. Also, if they've engineered it for .357, you're very unlikely to have to be worried about a hot .38 +P load. If weight becomes the overriding concern, something like a 442 becomes the clear choice and you just accept that you're carrying standard pressure .38 special rounds.
Again, my experience is relatively unusual. My garrison commander, Mrs. Ace Midnight, prefers large framed revolvers - she has a 686 (either the "Border Patrol" or "US Customs" model - I just don't recall) that her father is in possession of currently, and her ready gun is a 8-shot 627.
In larger framed revolvers, .357 is fairly manageable, even with shorter barrel lengths. In J-frames or small, light revolvers like the LCR or SP101, you will have to experiment with light .357 or .38 +P loads to find what meets your stopping power and recoil requirements.
This post was edited on 1/30 at 1:54 pm