Bowtech Insanity CPX 290 fps with a 453gr arrow. I have noticed that they don't penetrate my target as well as the nap thunderheads I have, but after some tweaking of my D Loop all of my broadheads are hitting exactly where my field tips are so I don't think I have anymore tuning issues. There is only an inch or two difference between the two heads so it isn't too big of a difference. I'm just wondering if there is too much blade there to punch through hide, bones, etc. I have noticed they aren't quite as forgiving as well... Any kind of torque throws them off a few inches at 50, but I'm hoping I can be like WapitiBob and get one at two steps... I'm thinking anything will work at that range!