The KE will almost always be the same within a few lbs because your bow will only put out so much energy. However the momentum will always increase with heavier arrow and this can help with penitration and down range energy. If I shoot two arrows at a target 20 yards away, one being a fast light arrow and the other being a slow heavy arrow (300 grn/400+ grn) the heavy arrow will hit the target much harder. You can see and hear the difference at the shot.


There is a reason why traditional archers shoot heavier arrows, they just work better out of lower power set ups.

Paul