For what it' s worth, the 348gr Power Belt was the most accurate of the Power Belts in my Encore. I had good luck with 100-150grs of powder, behind this bullet.
I didn' t have much luck with the other weights, the accuracy was only average.
Finding what each and every rifle likes the best.
My pet load is the 289gr. Remington Copper Solid with 3, 50gr. Pyrodex Pellets. My 2nd choice is the 300gr. Barnes MZ.
The loads I work up for my guns are all on the heavy side. I don' t play around much with anything under 100grs. I want to maximize my effective shooting range by finding the most accurate/hardest hitting combination I can.
Even if I were shooting rats in a garbage dump, I' d be nailing them with all that I can get out of whatever gun I' m shooting at the time.
Good Luck with finding a load with your Encore. That' s more than half the fun of shooting muzzleloaders.
Keep it in the 10X