ORIGINAL: Huntingtherut

Im shooting a T/C Black Diamond 50 cal. I use 90 grains of black powder with240 gr hollow point hornady sabots. Off of a rest aiming at the bullseye, my hiting points are at 50 yards +2, 100 yards +3, 150 yards+1, 175 yards -5. Basically, my bullet seems peaked out at about 100 or 125 and is dropping 6 inches from 150 to 175. Does this sound right?? Any feedback would be beneficial. Thanks