Mike,
Here are the specifics: Total weight of the arrow was 650 grains, it was tipped with a 190 grain Grizzly El Grande, and arrow penetration was 16 inches. One factor that affected/diminished penetration was poor arrow flight, the nock end was tailing about four inches. The shot on the bison was eighteen yards quartering about 20 degrees with a sixty mile an hour tail wind (yes 60 mph with gust to over 80 mph and 12 degrees without the wind chill), which caused the poor arrow flight. The bow is 58# @ 29” semi-snakey Osage with big horn tip overlays; it’s not the fastest bow I have made but it isn’t a dog either.