My first bird was taken with a muzzy 100gr 3 blade, shot, cut the wing and he dropped.

I have switched over to the Rocket broad head, and an using the hammer head, it has a 2 inch (3 blade) cutting diameter. I shoot at long range and the muzzys didn't cut it a 50 + yds

but my bow shoots over 270 fps which is the recommended speed (or faster of course) for the head.