Acutally Mike its the whitetail you shouldn't shoot at 50 yards but I am sure you knew that. Mulies are quite lethargic by comparison. Out west a 50 yard or more shot is quite common with a bow.
I forgot to qualify my earlier post. With the acception of the Paradox and its variants they all hold a lesser weight at full cock. Again with that one acception they all have a degree of let off. Like my compounds vert bows compound crossbows do not hold full weight at full cock which is why the compound crossbow is easier on the servings.