Picture yourself deep in the backcountry, bow at full draw, an elk broadside in your sights, the feel of the string against your nose and your hand anchored against your cheek. You release your arrow and are rewarded with that light thump of the arrow passing cleanly through the elk to embed in a tree just behind. The elk runs off, and you hear it crashing down through the brush out of sight in the distance. You’re able to locate your arrow quickly and feel the triumph as you see it covered in bright red blood, along with a clear trail leading from where the elk stood to where you saw it disappear into the trees. You follow the trail of red to find what we all hope for at the end of a hard hunt, your target elk piled up and ready to quarter and pack out of the backcountry.
Now, let’s replay that same scene in your mind, but with a twist. This time, the arrow doesn’t pass through fully. Maybe it fouls slightly on a rib or just doesn’t have the force to push fully through the body cavity, embedding itself and, potentially, staunching the flow of blood and masking the trail you so desperately need to follow. The rest of your day (or days) is spent gridding the area in hopes you’ll find a drop or two to guide you to your kill. You’re reminded at that moment that the fine line between success and frustration in bowhunting can hinge on a countless series of variables, some of which are within your control – like your arrow setup.
Delving into the realm of bowhunting arrow setups reveals a nuanced and ongoing debate that often centers on arrow weight and its impact on kinetic energy. While I admit my limited expertise, I’ve constructed my approach through a blend of thorough online research and insights from seasoned experts like John Stallone and James Nash. Take, for instance, my elk hunting setup for this season – a meticulously crafted and well-tested combination of an Easton Axis 5mm 300 spine arrow with 3-fletch Bohning Heat Vanes and a 100gr Iron Will Impact Collar, topped off with a formidable 150gr Kudu Point broadhead. This arsenal is unleashed by my Hoyt Carbon Defiant 34 at 70 lbs of draw weight and slightly over a 30″ draw length.
“uMmM… aAaAaAcTuAlLy, YoU lOsE kInEtIc EnErGy WiTh An ArRoW tHaT hEaVy!”
Yes, we all know that, but I don’t care.
But let’s address that elephant in the room: the perennial critique that a heavier arrow leads to the loss of kinetic energy. Switching back from my current 572gr setup to my previous 500gr arrangement yields a mere four foot-pounds increase in KE (roughly from 84 to 88 foot-pounds) – akin to the force of a high-end BB-gun, which is, in essence, negligible. The real benefit of the heavier arrow lies in the myriad advantages it offers – enhanced stability, heightened durability, improved wind resistance, and, most crucially, the EXPONENTIAL BOOST IN MOMENTUM.
Forgive me if I slightly mangle the sciencey terms. But Kinetic Energy (KE) quantifies the energy potentially transferred upon impact. It’s the principle that allows a teeny-tiny bullet to wreak havoc on a massive moose; the KE transfer is so potent that it induces severe shock trauma within the moose’s vitals. However, this is where the plot thickens – for bowhunters, KINETIC. ENERGY. IS. NOT. AS. IMPORTANT. Comparatively. While minimal shock trauma accompanies the arrow’s hit, the true devastation stems from the blade’s cutting trauma, causing fatal hemorrhaging. And for that lethal cut to occur, penetration is paramount.
Enter momentum – the unsung hero in this narrative. Unlike KE, which, as mentioned above, is an energy measurement, Momentum delves deeper into the physics of motion, specifically the force necessary to arrest a moving object. In other words, it describes the sheer force needed to bring an object in motion to a standstill. When we apply this concept to bowhunting, it equates to the arrow’s critical ability for successful penetration on impact with an animal’s thick hide. And here’s the kicker: a heavier arrow setup yields greater Momentum, which, in turn, yields greater penetration.
Back looking at my current build and comparing it with the former 500gr setup, the momentum difference increases by 0.028 slugs (from 0.626 to 0.654 slugs). Initially, this doesn’t seem revolutionary. But that added 5% penetration potential can equate to over an inch, depending on your setup. I’ll opt for an extra inch or more of penetration over the added BB-gun’s worth of energy-transfer potential any day of the week. Plus, let’s face it; we don’t always make perfect shots. I’ll put my heavy arrow with its solid 150gr broadhead and impact collar against a lighter setup any day when it comes to unintentionally loosing an arrow directly into an elk shoulder.
What do all y’all think? Let me know in the comments.