Roy -
Take this with a grain of salt - just got my .357 bbl and have taken it to the range ONCE.
4 bullets loaded last year.
148gr wc was the worst
160gr wc was ok
170gr RN was ok
200gr Flat RN was best
Mine has a LOOOOOOONG throat. An RCBS 35-200gc will engrave into the rifling and leave 1/16" CLEARANCE between it and the empty case.
I haven't tried small light bullets, nor anything jacketed yet, nor different loads with wc's.
Still room for lots of testing.