The Traditions inline will handle 80gr of BP or Pyrodex although I do use 80gr T777 with the 260/320gr real bullets and back down to around 70gr with heavier stuff. I shot some 398gr minnies with 80gr. of T777 and I'll tell you what
after 3 rounds THAT HURTS BAAAAAAD. The previous poster was right T777 burns more like smokless powder. If you would like more info on my loads/data I posted a bit on GB's site around 1.5-2yrs ago do a search on traditions buckhunter pistol at blackpowder forum. The sabots I tried did not perform at all so stick with full lead conicals they will do 1.5-2.5"@50yds no problem.