a good buddy of mine who has since passed away shot a Bison with my Ruger SRH about 15 years ago using one of my 370 gr cast bullets from a Ballisticast Mold that was about a 15 BHN. I think the load was 20 or 21 grs of 4227 so about 1000 to 1075 fps, some where in that range (guessing) The distance was about 20 yds as it was just a harvest bull about 2 years old. He shot it in the head, face on & Ron, the guy with him said it's hind legs kicked the belly so fast you could hardly see it.I think if the bullet had been going faster it might have failed, just my thoughts.
Dick