Bill: Based on my personal experience, I would recommend you use a short conical, like the Lee R.E.A.L. of Buffalo Bullette conicals, when hunting boar. They deliver more energy than will a .50 cal. RB, and they will have no problem going through that shoulder blade. Expect your shots to be close- pistol range- so accuracy is not the real issue. You can place the ball or bullet where you want it to go at those short ranges.
A friend shot a wild boar with his .62 caliber rifle, with a PRB, and the ball entered its chest, and traveled the lengh of the mature boar, ending up in the ham on the opposite side. The boar stood where it was struck, while Don reloaded his rifle as fast as possible, standing only 20 feet from the boar. His guide had climbed a tree. The Boar shook, and collapsed just as Don was about to put a second shot in him. I had timed Don in his reloading of that rifle, and he was reloaded in 20 seconds or less. When he saw all the organs damaged by his large RB, he was amazed that the boar could live so long.
He was hunting turkey the year I took my first Boar with my .50, and after discussing the shots on my boar, and those of two other friends who used .54 and .75 caliber guns, the 4 of us concluded that the RB would certainly kill a wild boar, but that we would recommend using a conical to other hunters, since the boars seems to take a bit of time for the " DYING " part of the kill. There is no point in tempting fate. The second boar hunt I went on we had seven hunters shoot boars, and we had 3 charges out of the seven kills. No hunter was injured, but one guy was running around a large tree, being chased by his boar, until he managed to fire a rifled slug from a short barreled " riot gun". he had into the boar's chest. The man who shot his boar with a T/C .54 Maxiball had the only one shot kill for that hunt, with a chest shot at about 10 feet.
You don't need a huge powder charge- just a well constructed conical to do the job NOW!