Pushing him had nothing really to do with it. He was probably dead 30 seconds after the shot. You really didn' t push him. 171 yards is a long way to go with a double lung. Must have been low or something and just knicked one of the lungs and skewered the other. Give us the low down on the broadhead you used. Anyway, it' s not unusal to not get a lot of blood the first 30 yards.... That' s 3 hops and a jump. If you hit high it takes a while before the start putting much on the ground .... if they ever do. You didn' t push him.... you just missed the trail. Maybe you need a brighter light?