lemoyne

Cayugad is close as usual. For some internal ballistic reason Triumphs seem to draw the line at 120 gr of 777 with Shock Waves, you might be able to go higher with Blackhorn but proably not it. Best way is to start low 90 gr will do, then after a number of groups say 4 try 100 the same way, you will end up between 100 and 120 with most Triumph's but while they are one of the most if not the most accurate muzzleloaders they do get erratic if you put in more powder than they like; 10 gr to much and almost any muzzleloader will. The kind of powder makes a difference in that to.
After you have 50 to 100 shots through it and the barrel starts to get a polish it will group better. Personally I use something like the FPB from Hornady to break them in as that works a lot faster. Normally I would expect better even at first. Your bullet+sabot diameter is very important it should require both hands to push the combination down but never be so tight that you need to pound on it.A very solid rest with sand bags frount and back can tell you what the gun is doing anything less introduces to much human error.