Loose pyrodex 110 gr and 295 powerbelts work very well for us in all or our T/C's. I like the loose powder over the powder because you can adjust your groups in 5 grain incriments vs 25 or 50 with the pellets.
3 triple seven 50's followed up with a 250 gr Hornady SST shoot the best out of my pro hunter. I shoot the the black sabots, They are tight to load, but they touch holes at 100 yds. If you don't mind a little recoil. They group very nice out to 200 also.
You will find everyone has their own ideas and almost all shoot some different load. One thing for sure is that every gun is different and most of the fun is finding what works for your gun. I can only say that when I bought my Encore I spent allot of money on powders and bullets and spent time on the range shooting groups and chronographing the loads. No powder I tried gave the velocity of loose Triple 7 grain for grain and that was by a long shot. The other thing I found with 777 was the consistency. I settled on a 120 grain load and my velocities were always between 2215 & 2218. I can't get that consistency with my metallic reloading. As you can imagine that consistency produced tiny groups as well. I found it was diminishing returns velocity wise above that as most of the powder was being burned outside the barrel and had no effect on velocity. I use the 250 grain Barnes Expander which has been an excellent bullet for me. I have heard good things about the shockwave and also the Staghorn powder and will try them this spring to see if they can top the 777.
My T/C Pro Hunter shoots well w/ 120gr. 777 loose powder, and T/C's 250gr. Shockwave sabots or Hornady 250gr. SST's; both shoot well for me, however I have to run a wet patch after 2 shots, (rotten powder ring). I used the Nikon Omega BDC atop my T/C this year on a 9 pt. the last day of rifle season.
When the smoke cleared, he was lying where he just stood, very exciting.