Leaning towards flatline or velocity. Watched my friend shoot his maxxis 31 through a chrono 28 inch draw, 66 #, 27 inch arrow 400 spine---Axxis 268 fps, epic 280 fps----flatline 288 fps---flatline had this gain while only loosing 1 Ibs of kenetic energy. I hear flatline and velocity are basically the same arrow. I also like the idea of the victory VAP, but wasn't able to see one chrono'd or shot. Hear the have alot of penetration. Seeing was believing; I was concerned on losing energy or penetration, But the math only shows 1 Ibs loss KE. Anymore ideas. Or something I've missed?