So... I was at the range. Started with some .38 special. Shot some really good 25 yard groups. When I started with .357 a cylinder or 2 went through with no hitch. Then it started to get hard to cock. Then impossible. I checked the ejector rod, it was tight. If the cylinder is open and the trigger/hammer cycle fine. Everything I could think of was checked, wiped, lubed. Opening and closing the cylinder is very, very hard but if it's indexed a certain way goes in easier.
I took the side plate off, sprayed it with gun scrubber to get the grease off and check for loose parts. Nothing looks out of whack.
So, diagnose my broke gun.