You have to use 5.5" feather fletching to get them to come anywhere near to flying straight. Also notice the speeds in the vid are very close range w/ pretty slow bows.. by todays standards. What happens at 20-30yrds w/ a bow w/ any kind of speed.

Ind the video the blades do break off after hitting the bird.

I don't know about you.. but where I hunt.. it's not out in an open field. The slightest twig or blade of grass would send this head careening far off course.

Also was told at the ATA show at their booth that "these don't work if shot at the body"..