I would take a look at the slick trick heads
www.slicktrick.net Before I switched to these heads my broadheads were about 2 inches low from my field points. The slick tricks group with my field points now even to 40 yards. I don't shoot the 310 FPS like you are but you might want to give these a try with the higher speeds you are shooting. Of course I will defer to 5 shot on any broad head selection with his extensive testing. I'm going to use them starting Sep. 1 on some bears in MN. I'll let you know how well they work.