I can certainly understand a .22 getting that reaction, especially at 50 yds. being the size it was..... it's the 30 yds. with a muzzleleoader that baffles me...
I have had no reaction at all from at least three hogs that were hit solidly at close range with a 240 grain .430 bullet fired from a .50 cal. muzzleloader. Knew that i had hit those hogs and all were recovered: Even saw the dust fly off one hog when the bullet hit him in the shoulder. Had no reaction from a 275 pound boar smacked with a .30 caliber 150 grain Core Lokt that hit him at over 3,000 fps, he just took off at warp speed: That one made it about 200 yards with a good blood trail.
Sometimes they just do not show any sign of being hit.