Momentum and FOC are more important than KE. So, I shoot 300 spine shafts, a heavy BH (150gr) and brass insert to help w/FOC. My FOC is approx 18% My arrow weight is 500gr and speed out of two of my bows is 286 (Hoyt Trykon XL) and 308 (Mathews Monster), both set at approx 70lbs. KE is 90 and 105ft-lbs, with momentum of 0.6 to 0.68, respectively. My draw length is 31.5.
Another very good reason to shoot as heavy an arrow as you can and still get acceptable flight (i.e., not a rainbow arc) is that as arrow weight is increased, the bow is able to transfer a higher percentage of its stored energy (potential energy) into the arrow (i.e. much more efficient). Less of the bow’s energy is converted into wasted energy (like vibration of limbs, riser and string). Your bow will be quieter and smoother to shoot!
Also, the more FOC you have, the faster an arrow will stabilize after it leaves the bow, plus it will penetrate the target better as the having the weight forward on the shaft will cause less lost energy on impact and will actually help guide or pull the arrow thru the animal.
ET
