Arrow penetration is without a doubt one of the most important factors in recovering more animals as a bowhunter. Why might this be?
A good blood trail can make or break any shot. I have made excellent shots on animals that have ran under 60 yards, but without an arrow exiting the animal I was left with little or no blood making even a short track job like that a challenge.
To get a good blood trail, an exit wound is nearly required.
That’s not to say people haven’t had great blood trails come out of entry wounds, on shots where your arrow never exits. It happens, but most quality blood trails you see will be a result of getting a complete pass through of your arrow.
There are five key factors that come into play when maximizing your arrows penetration, and we are going to break them down for you to help you roll out more red carpets on your bowhunting adventures.
Arrow Diameter – Do thinner arrows penetrate better?
Arrow diameter is something that I find gets overlooked too often by archers. There are generally four sizes of arrow diameters. In order from smallest to largest we have micro, small, standard, and large.
The first three are your hunting sizes, the large diameter arrows are typically only used in target archery so that your arrow cuts more paper on the target, giving you a better chance of hitting the X-ring.
Standard diameter arrows are the classic, typically a 6mm diameter design that has been around since the invention of carbon arrows.
Over time, a 5mm small diameter shaft was developed. Hunters liked this idea a lot, and eventually a 4mm micro diameter became an option on the market and is an extremely popular choice for bowhunter’s today (including myself).
So, do thinner arrows penetrate better?
There are several benefits to shooting micro diameter arrows, and very little downside (if any). You may think that a smaller diameter arrow will be lighter or weaker than a standard diameter. The opposite is true.
To stay competitive, arrow companies had to make these new skinny arrows in the same weight ranges as their standard counterparts, so that people would not be passing on micro diameter arrows because they didn’t match their setup.
A micro diameter arrow packs the same weight into a smaller package.
In other words, the carbon fiber that the arrow is made of is denser on a micro diameter arrow than a standard, making it stronger.
Micro diameter arrows are also less impacted by wind. This one is simple; less surface area means that there is less for the wind to be able to push around.
Lastly, for the same reason as above, a micro diameter arrow will penetrate better than a standard diameter.
Think of it like this. You take a pencil and poke a hole in a piece of paper. Now you pass the pencil through the piece of paper. There will be friction and contact between the paper and the pencil the entire way though.
Now, you take a knitting needle which is much thinner than the pencil and pass it through the same hole. There will be significantly less friction, as the knitting needle is skinnier than the hole, thus it will pass through easier.
This is exactly how it works with arrows. You are using the same broadhead no matter what arrow diameter you use, so the size of the hole is a constant. But when you try to pass a thinner object through that hole, it will go through much easier than a thicker one.
Next time you are at the range with some buddies, pay attention to everyone’s arrow diameter. You will see a direct correlation between whose arrows bury deepest in the target, and arrow diameter.
How can you increase your arrow penetration? – Paper Tune!
Paper tuning is simply the processing of getting your bow, arrow rest, and arrow setup compatible to the point where the tail of your arrow perfectly follows the point during flight.
A bow that is not paper tuned may fire an arrow in such a way that the tail does not perfectly follow the point.
To visualize this, think about how a car looks when it is skidding on ice. It is moving forward, but the front may be pointing to the left of where it is headed, and the back pointed to the right. The tail is not following the point. This is an issue in archery for a few reasons, penetration being a big one.
When your arrow is flying like this, it will slow down faster. By the arrow being angled in its flight, more of it is exposed to the head on wind and it is now less aerodynamic. By moving slower, it will also naturally penetrate less than an arrow that is flying properly.
When an arrow that is flying poorly contacts an animal, the momentum of the arrow is not working the way it should.
When a straight-flying arrow hits an animal, the momentum of the arrow is pushing the broadhead directly into the animal.
Think of what happens if you are trying to push a car by yourself. If you push it from the license plate, it will move directly forward. But if you try to push it from one of the taillights, your pushing energy will not be as effective.
This is a huge factor that impacts arrow penetration. I have heard many hunters say, “my arrows hit where I want them to, so why would I paper tune?”
This is exactly why! You may be hitting your mark, but you are wasting your arrows energy and sacrificing valuable penetration by not taking that extra step and making sure that your arrows are flying straight.
Lastly, it is very worthwhile in mentioning that an arrow flying out of a paper-tuned bow will be more accurate than out of a bow that is not tuned. This difference in accuracy will be magnified at long range, and again when you add a broadhead to your setup. Remember, most bows shoot field points very well. However, a properly tuned bow/arrow combination will shoot most broadheads just as well.
Weight vs. Speed – Do heavier arrows penetrate better?
This is certainly a hot topic in the archery community.
Many hunters feel that having a heavy arrow to penetrate deep is the most important thing while many feel that getting the arrow to its mark as fast as possible is the most important factor. I am here to tell you that both factors are very important, but we must look at the physics of archery to assess the truth.
An arrow, like any projectile, has an optimal speed at which it will fly with the best possible flight characteristics.
What this means, is that there is a particular speed at which your arrow will spin the most consistently, and flex at the most efficient rate for it to reach its mark as consistently as possible. You see this a lot in the world of precision rifle shooting.
When building a load for a rifle, you will generally come to a point where you have added too much powder to the casing, increasing your bullets speed, but now your groups are less tight. That bullet was simply not designed to fly as fast as you were trying to make it fly.
The same factor applies in archery. Every projectile has an optimal speed at which it is designed to fly.
For arrows, we (along with many other sources I have chatted with) have found that arrows fly best and group the best in the 270-280 fps range.
That is not to say that you won’t get good groups at higher speeds, but this range is what we have found to be best. To bring in the importance of weight to this discussion, my philosophy on building the perfect arrow comes down to this. Shoot the heaviest arrow you can, while maintaining a speed in of 270-280 fps.
If you are shooting 300 fps, you should add some weight to slow it down, and this will increase your arrows kinetic energy and therefore penetration. If you are shooting 260 fps, you should take some weight away or increase your draw weight to bring your speed up.
This simple mantra has been remarkably powerful for me in my bowhunting over the years, and in the dozens of bows I have setup for people I have never had someone come back with a complaint while using this philosophy in their arrow setup.
This combination of speed and weight will give you the best of all worlds. Great penetration, impressive speed, and the most ideal arrow flight ultimately leading to more accurate shots, more pass throughs, and bigger blood trails.
Broadhead Choice Broadhead choice will play a large factor in arrow penetration
The same principles as in previous points applies yet again here.
More surface area trying to pass through something will result in it being more difficult to pass through.
By this logic, a field point will be the best penetrating option. Of course, we need blades to do more damage so where does that leave us with broadheads?
A smaller cut-diameter field point like our 1” standard fixed-blade will penetrate better than a head with a larger cut. Less material to move through the flesh means it moves through easier.
The trade off with this is of course that you are getting a smaller hole, so your personal archery philosophy and typical hunting scenarios will have to come into play with that decision.
When it comes to fixed blades versus mechanical broadheads, fixed blades are without question the better penetrating option.
A mechanical broadhead requires energy to open on impact, slowing down your arrow and thus negatively impacting penetration. Therefore, mechanicals are not often recommended for people with low draw weights.
Many mechanical heads also feature 2” or greater cutting diameters. This can certainly leave impressive wounds, but the sheer size of the object that you are trying to pass through an animal will impact how deep it goes. Consider this especially in the case of a less than ideal shot.
A compact fixed blade will certainly go deeper in an animal’s shoulder than a wide mechanical will.
Shot Placement – How it affects arrow penetration
The last point that is worth mentioning when talking about how to maximize penetration is shot placement.
This is something that you only have a certain degree of control over, making the previous points even more important to consider in your archery setup.
If you hit a shoulder, you are most likely not going to get a pass through. However, you can build yourself an arrow that will be more accurate (and less likely to miss and hit a shoulder) and one that if it does hit a shoulder will perform reasonably well.
Shooting an animal in the ribs is a similar discussion. If you hit a rib, your arrow will certainly slow down compared to an arrow that passes cleanly through just the rib meat on both sides.
Of course, you have zero control over this.
What you do have control over is the thought, attention, and science behind your arrow build. It is your responsibility to build an arrow that will perform in any scenario, even those that we don’t plan for such as hitting shoulders.
With these tips, I hope you are able to rethink your arrow build to maximize arrow penetration and draw some bigger blood trails on your next hunt!
Does a great job bringing the broadhead back to OEM sharp, just a little bit of oil and go smooth. I would recommend if your broadhead is not in bad shape as a touch up but luckily a buddy bought the 320 grit just in case we need it to really bring one back to life.
I'm not great at sharpening knives (or broadheads), but this tool is essentially foolproof. The design also makes it unlikely that you'll slice or stab yourself.