I'm not that high tech
But I did some online research, I think I googled "Muzzle loader barrel length"
found a write up about some one who did crono differant barrel lengths, no drop burning ~100 grains going from
~26" down to ~21".
Now take into account I am East coast (Maryland), I hunt from climbers in the woods, most shots are 20-60 yards, a few out to 90 yards, and the once in a couple years ~120 yard shot, and I am shooting with 80 grains of powder.
So for a tree stand gun shooting under 100 gr powder I see no problems, and I am getting 2" groups at 100 yards with only about 15 rounds through it in 1 range session(260 gr bullet, ~1" high at 50 yards).
I feel I can get 1" groups at 100yds with more range time and a trigger job.
BTW, 80gr powder in the 20" barrel has had 5 pass throughs so far this year, I am stepping up to a 300gr bullet, as I have excess energy so far.
Slack