Very interesting line of thought on this topic. I hope others with more insight and experience (just a couple who come to mind; Dr Ashby, Troy Breeding, etc) will tune in and share their thoughts and knowledge on this one.
I learned to build and tune FOC arrows 4 years ago and haven’t looked back.
I will share my findings and experience briefly to help the conversation along.
We all know within these circles, that FOC Mass pays more gains in arrow flight and penetration than speed. Dr Ashby’s research has shown us how and why, especially when the arrow meets resistance in the form of bone and soft tissues. The research also shows how having the high mass on the front end of the arrow literally “pulls” the arrow through the resistance medium.
I think some keys points of FOC arrows to remember are as follows;
They recover from paradox faster than a non FOC arrow, allowing more energy to be conserved to pull the arrow in a straight line towards the target.
This aids in less to no oscillation as the arrow enters an animal, again conserving energy and making the arrow more efficient as it is “drawn” through the hole it creates. The arrow/broadhead has an easier time passing through the animal and whatever resistance it meets.
FOC arrows are quieter, they absorb more energy from the bow and convert it to down range momentum.
FOC arrows are quieter due to requiring smaller A&A fletching to control them in flight.
FOC is more stable in flight when encountering cross wind, hitting grass or twigs due to the majority of the mass “drawing” it forward while not oscillating.
FOC arrows are more forgiving of poor form. Once you point that mass at an object, the mass is drawing it to your point of aim.
Dr Ashby’s YEARS of documented research have proven these facts. An arrow is way more efficient when being drawn to the target rather than pushed. That is why a tuned FOC arrow shot out of a 55# bow will out penetrate/perform a low FOC arrow shot out of an 80# bow.
Total mass in an arrow is less important/has less effect on efficiency and penetration than greater FOC in a lower mass arrow, to a certain degree. (ie At least 25% FOC and 650 grains total weight)
An arrow is a system of components and the total of adding those favorable FOC components up. (ie. Type of broadhead used, level of sharpness, tip angle and design, degree of proper tuning, external/internal footings for structural integrity, how many “weak links” are in the arrow system, etc)
Again, this is based on my interpretation of Dr Ashby’s research and lectures.
Do i want to shoot reproduction cedar BEAR arrows with Bear razor heads sharpened with a file and 5 1/2 inch shield cut feathers? You bet I do! They are historic, nostalgic, and plain sexy. Will they kill animals? You bet, many animals have died to such arrows. Will they perform well when I get a bad shot, hit bone, shoot in a heavy cross wind, or I hit a twig? Not nearly as well as a high FOC arrow. The proof is in the pudding. I have taken several animals with light FOC arrows, and lost some due to poor penetration and murphy’s law. I have taken several animals with high FOC arrows, and lost only one due to my own poor shot placement (one lung hit, animal made it to private property where I wasn’t allowed to search and recover). I have payed close attention to the wound channels and damage created by FOC arrows and sharp single bevel broadheads. They do their job very well and bring home the meat. They account for more uncontrollable factors which would normal result in a poor shot due to wind, deflections, animals taking a step, poor hits. Accuracy and penetration is the name of the game. FOC arrows do that.
My humble opinion is thus; develop the highest FOC arrow you can, which works best for you and the bow you are shooting, animal you are hunting, and stay over 25% FOC and 650 grains total weight.
I look forward to other thoughts