I believe it is extremely rare to penetrate a shoulder bone with a "smack dab" shoulder shot on a "nice" buck (say 2 1/2 yrs. or older). It all depends exactly where it hit, but with my two experiences they were goners. One I almost shot again two days later. Is it possible it only penetrated 2 inches and broke off2 inches outside his body?Nevertheless an all out search is a must. Good luck, hope you find him.