problem is the arrow lost so much energy when it broke the front leg that it didn't exit leaving a lower blood channel. The shot doesn't sound to have been perfect but I agree the deer is dead and you can probably find him. I would encourage you to go back in and hopefully remove the rack and tag it. I have posted here before that the best shot is 3-4" behind the shoulder broadside high/low double lung shot. Hunters need to wait for the best shot or pass. Good luck in finding the buck and let us know how it all ended.