I thought I would add a little more about the big conicals. Using the Lymans Black Powder Handbook and Loading Manual, I noticed that with the big conicals more powder doesn't really make em go that much faster. This is a .54 caliber, 1-32 twist, 32" BBL, 450 grain Lyman Bullet using Pyrodex RS, cci #11 cap:
60gr 1143 fps
90gr 1360 fps
120 1521 fps
So at some point you have to wonder about diminishing returns. Keep in mind that terminal velocity @100yds is only a few 100 fps less than muzzle velocity. In the old days the Black Powder .45-70 was a 500 grain bullet with 70 grains of black powder. It effectively handled all game even Buffalo.
Shooting a 450 grain slug at 1100 fps is really an effective round. It's actually faster than your average .40SW bullet at muzzle velocity, and 100yds downrange is still faster than .45ACP at muzzle velocity. Also at 65 grains it's comfortable to shoot and extremely accurate, or at least much more accurate. Just some of my thoughts on the subject. Happy hunting!