OK? Okay, Time for a New Arrow
by Darren Choate
After having hunted antelope–unsuccessfully–in Arizona, my next hunt will be an archery whitetail hunt in Oklahoma with Bend of the River Outfitters. I will still be using my Mathews Halon 6, but I have scraped my speedy antelope arrow for a more efficient, energy arrow. For this hunt, I was looking for something that will approach 100% of the kinetic energy available from my set up with a momentum measurement approaching 0.50. Though kinetic energy (KE) has been the standard for years, I prefer to use momentum–a mathematical calculation of energy–to predict arrow penetration, rather than KE, which is a measurement of potential energy.
My bow stayed the same: 60-pounds at 27.5-inches of draw. To make the change in arrow, I went back to our Arrow Efficiency Calculator. Knowing I shot my 315-grain antelope arrow at 309 FPS, I entered that data to find the most efficient arrow weight for my new whitetail arrow. The results suggested a weight between 400- and 428-grains. With the disadvantage of my short draw length of 27.5-inches and my draw weight of 60-pounds because of a bad shoulder, I decided to go with the fastest arrow within that range, something right around 400-grains.
I then went back to our Arrow Weight Estimator, to search for the perfect energy arrow, and chose the Easton FMJ6. At 60-pounds and approximately 27-inches, the perfect spine was 390, which weighs 9.7 GPI. My completed arrow, with 100-grain Wac’Em, weighed-in at 403-grains. To complete the project, I fired a group of arrows through the chronograph, with the average of 276 FPS. Again, I entered this data back into the Arrow Efficiency Calculator to check my energy, and was pleased with the following results.
- Mathews Halon 6 | Easton FMJ6/390 | Wac’Em 100-Grain Fixed
- Speed: 276 FPS
- KE: 68.10
- Momentum: .4935