The Optima I had loved hornady 250 grain SST and blackhorn 209, I never tried powerbelts in it. Powerbelts seem to have people that swear by them or swear at them, just keep in mind that they are basically a soft lead copper washed bullet. IMHO the people that don't like them push them too fast, I killed 5 for 5 deer in one season with powerbelts out of an old Knight percussion gun I owned. I shot them like I did my bow, double lung shots only. The only deer that went over 30 yards I shot low and got into the shoulder, he went about 150 yards with practically no blood trail.

Main thing is shoot some different load combos to see what your Optima likes.