In my Optima I went to a Blackhorn 209 breech plug from CVA, and I have been shooting BlackHorn Powder. Because of some recommendations on this bullet for whitetail, and getting a heck of a deal on the bullets, I have been shooting the .40 caliber 200 grain Shockwave in the dark blue sabots. I too have a scoped rifle. This is what mine will do with that bullet at 52 yards.
At 100 yards I have really not played with the rifle that much. Other then shooting some paint cans, shooting oranges off a stump, that kind of thing. The Optima seems to like 90-100 grains of powder. And its a great shooting rifle. I never shot the TMZ barnes out of it. I have shot some Hornady PT Gold in 260 grain and they did real well.
As for powerbelts.. a 245 grains aero tip powerbelt is crazy accurate out of this Optima. I was sent some to play with, and theh accuracy shocked me. I really think I could take a deer with them. Even though everyone else will tell you they are horrible bullets. But deer hunting has been ruff around my place the last couple years.