Free: Contests & Raffles.
I practiced a lot out at 150yds this past year, would have been very comfortable with that shot, then called my bull into about 10 ft. I'm like a sniper at that range
With the "open sights" rules in effect in Washington for muzzleloaders (i.e., no scopes!), I have found my effective range for a deer-sized animal to be about 100 yards. Using a peep sight has extended this to about 110-120 yards, but I am usually reluctant to shoot that far. I hope that helps!
I shoot a Traditions Evolution, can get 1 1/2" groups at 100 yards and 4" at 250. Not sure how much power it has out past 250 but at 200 it still has enough punch to kill and elk. I personally won't shoot at an elk or deer over 150 with it just to be safe. I much prefer under 100.
One other thought is that your maximum effective range will also depend on the position. For me, to keep bullets reliably within a 4-5" group (to fit comfortably within the vitals of a deer):-prone or tree stand with shooting rail: 100-110 yards-seated position (on ground): 75 yards-kneeling position: 60 yards-offhand: 45-50 yards