This happend more often than one might think. I was with my brother when he shot a nice 4point in the shoulder with a 30-30. The buck ran off with a broken shoulder. I didn't find a single drop of blood until 5 foot before the buck dropped. The buck only went 50 yards over a hill and into a swamp. The only reason i found that deer is by gridding the swamp for a while. The key is never giving up.