IDPA,
IDPA was created so the average Joe could take his REAL WORLD gun and compete for practice. Not for money nor trophys.
Okay, so some folks are in it for the fun of it. Fine, their choice. And some are in it to boost their ego by winding up on the top of the score sheet, and nothing else matters.
For what it's worth? If you have arrived at the conclusion you'll more than likely be packing your 2.5" when the SHTF. Then use loads equal in bullet weight AND velocity...in .357 cases. Anything less, you're just cheating yourself.
It's kind of like the old joke about boxing. The guy looked great in the gym, in the ring is where he had problems. Then of course, punching bags don't move a lot or punch back either.
Enjoy and good shooting,
Murphy2000