Folks have been using Sierra's HPMK's since they came out in 1958. They often blow up too soon on impact depending on their striking velocity and tissue characteristics. Sierra's put in print not to use HPMK's for hunting. People do what they want.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master