a 45 lb bow shooting 280? holy cow that seems awful fast. Anyways when using a lower poundage bow i would stay away from any mechanicals, instead look for a good cut on contact head, the magnus stinger would be a good one to look at...proven design and not that expensive. you might want to consider a slightly smaller head too, like an 85 grain, but as long as the blades are nice and sharp a 100 grain head should be ok.