I've not shot them into a whitetail before, but mine fly great too - and I've never been able to get fixed heads to fly worth a poop! I'm shooting the Spitfire Maxx's this year, but will try to kill a doe or something with the bloodrunner.
With that being said, we have many team members shooting the bloodrunners, and thus far the performance has been AWESOME! They make one heck of a mess - which is the point!