I've only been hunting with a ML for 3 years now and only have 1 deer to my credit with it....but I can't believe that the bullet wouldn't break the shoulder. I mean a 370 gr bullet and 90 gr of powder still has a fair amount of energy at 50 yds.

To me it actually seems like you must have shot low and hit the leg. That would account for the sparse blood and the bone fragments. As you were tracking through the snow did it appear as though one of the legs was dragging? That would indicatea broken leg.

Or, depending on your set-up, if you were using an inline that was sighted in high at 50 yds...(say dead on at 100)..you might have shot high and just clipped the top line of the buck. That would produce the hair and bone fragments as well.

Like I said, I'm rather new to ML hunting..(I shoot a T/C flinter, 350 Maxi-hunters, and 100 FF powder)..but I really can't believe that a 370 gr bullet wouldn't penetrate through a shoulder bone.

No matter where the shot was, whats done is done and we can't fix that. It sounds as though you put forth as much effort as possible into finding him, and you should be comended for that. Deer are very good healers, so he is probably out there somewhere alive.