Center Shots: How to Maximize Arrow Penetration
June 04, 2016
It is possible to shoot a deer through the shoulder and kill it cleanly? IF you build your equipment for that task. We're always looking for small things we can do to make ourselves more successful each fall, and this is more than a small thing. Yet, many hunters still ignore penetration concerns.
Why Penetration Matters
The standard formula for success when shooting at big game is accuracy first and penetration second — a close second. If you hit the lungs, the rest of the story will take care of itself.
But what if you don't hit the lungs? In fact, what happens if you hit the shoulder? The shoulder is only a few short inches away from your aiming point. It is not that hard to drift an arrow a few inches in the excitement of the moment, and there are always animals that move as you are shooting (or right after the string starts forward).
The fate of your hunt may then come down to a few inches (either regarding accuracy or regarding penetration). It puzzles me that people so easily and quickly assume nothing will go wrong. Plan for success, but prepare for the worst!
For that reason, I always rig up for maximum penetration. Over the years, I have hit several deer in the shoulder and still drove deeply enough to get both lungs and cause a very quick, clean kill. If you can punch through a shoulder and kill a deer, you can surely smoke a broadside hog. Let's dig into this subject a bit deeper and figure out exactly what we need to do.
Many experts recommend lower draw-weight bows because today's models pack so much energy that you can shoot through both sides of a broadside deer even with modest draw weights. In theory, a bow with a lighter draw weight is easier to shoot accurately. I agree, but only to a point.
No, you don't need a heavy draw weight to kill deer (or hogs) if you hit them in the lungs every time. However, if you hit the buck of a lifetime in the shoulder or front leg, you'll be glad you were packing a magnum — or wishing you had been.
If you can shoot higher draw weights just as accurately, you should. It really is just that simple. Every pound of draw force you add to your bow will increase penetration energy by roughly 1.5 percent. So, it is wise to pull the heaviest poundage you can handle accurately.
If you can draw the bow while sitting flat on your behind without raising it over your head, you can handle it in hunting situations. You should also be able to hold the string back for at least a minute without any kind of shaking. You can build up strength, too, so don't be afraid to turn your draw weight up a bit once you have easily mastered the current weight.
With their narrow width and reduced surface drag, today's micro-diameter carbon arrows penetrate better than aluminum shafts and standard-diameter carbon shafts of the same weight. Most arrow companies now offer one or more of these models. They tend to be a bit heavier than larger diameter carbon shafts of the same spine, and that also makes them better at driving deep.
Since arrow weight affects both penetration and accuracy, you must strike a compromise. Maximum accuracy at unknown ranges, and the ability to shoot through small openings, requires the flat trajectory of a light arrow. Also, the hope of reducing the distance a string jumper can drop before the arrow arrives is also an advantage of fast arrows. However, on the flipside, the more the arrow weighs, the more energy it will soak up from the bow and the better it will penetrate.
A good neutral point in this tradeoff is to shoot an arrow weighing somewhere around six grains of finished weight per pound of your bow's maximum draw force. A little heavier is also fine. So, if you shoot 65 pounds, an arrow (complete with broadhead) in the 390-grain range is pretty solid.
Any broadhead will perform well on soft tissue, but it takes a well-built head to hold up to solid bone. While not common, these hits do occur. Again, a deer's font leg and "elbow" are not very far from where you are aiming. Broadheads with stout, solid, steel tips and secure blade retention systems are the only choice when punching through a deer's shoulder or a hog's armor.
Some mechanical heads will do fine, but if penetration is the goal, you need to focus on those with a small cutting diameter. The bigger the cut, the more tissue (gristle on the hog and scapula on the deer) you have to mow through to reach the vitals. With soft tissue hits, this is no big deal, but when the going gets tough, I want a smaller head.
A cutting diameter of roughly 1¼-1½ inches is a good standard for either a fixed-blade head or a mechanical head when penetration is important.
Another consideration, if you are shooting a modest draw weight (anything under about 55 pounds) is the use of cut-on-impact heads. These style heads typically have two main blades and cut rather than punch their way through the hide. While these may not be quite as durable on bone hits as some of the replaceable-blade designs with big steel tips, they are very good at slicing through just about everything else.
Someday, you will hit a big buck in the shoulder or you will slam a hog in the shield from a less-than-ideal angle. Whether you recover the animal will depend almost entirely on the equipment you were using at the time. Choose gear that is built to penetrate.