Arrow Reverse Engineering
I’m a numbers guy when it comes to archery. As soon as I get a bow setup, I then start pairing that bow with an ideal arrow, but I typically make that selection opposite of what many archers do. I call it Arrow Reverse Engineering, or A.R.E. for short. When using the ARE technique, you have to start with your ideal arrow weight. You can be as broad of specific as you want. For example, for my elk hunt this year I decided I wanted an arrow weight of around 425-450 grains. For deer hunting I usually aim for the 375-400 grain range. But whatever your arrow weight is, the formula is the same. And it looks something like this:
(Total Arrow Weight – Total Components Weight)
Finished Arrow Length = Grains per inch for the arrow
This is, obviously, contingent on knowing the weight of all of the components that you are using for your arrow build. Fortunately, the archery industry is built on numbers, and you can find the weight of each of your components, usually accurate to within a tenth of a grain, either on the package or with a quick google search.
Here is an example using my ARE technique for my arrow build last elk season.
Step 1 – Do the math (Calculators ready?)
Broadhead = 100 grains
Lighted Nock = 20 grains
Insert = 15 grains
4x Pine Ridge 2.2 inch arrow vanes = 25 grains
Arrow wrap = 5 grains
Glue/Epoxy= about 5 grains (most people forget this part, but there is some real weight there)
That puts the total component weight at 170 grains. So, the formula looks something like this.
(435 grains – 170 grains) / 28 inches = 9.46 GPI
Step 2 – Explore your options (Google that stuff)
I shoot a 72lb bow, and I knew that my spine needed to be around 350. Finding a 350 spine arrow at 9.46 GPI is not very likely, so I expanded my search to anything from 9.4-9.7 GPI which gives me about an 8 grain window. Once I looked at those specs, the options really started piling up, so I added some addition parameters: I wanted slim or micro diameter shafts, but only wanted standard broahreading dheads sizes (nothing against Deep Six stuff, but if I’m traveling and have to get emergency replacement broadheads, the bench isn’t very deep for the Deep Six team at Wal Mart or the local small town shop). With those options and what was available to me, the Easton Axis 350 spine arrows with the HIT inserts were the clear winner.
Step 3 – Check your work (measure twice cut once)
Now that you have all of the information on your arrow and your components, double check your math. Make sure that the total arrow weight with your selected arrow and components falls within your target weight that you started with. There is nothing worse than thinking you nailed it, and then realizing you missed something obvious. For example, I once forgot to take the vane and wrap weight into consideration, a mistake that cost me more than 25 grains. If you have a small scale, definitely weigh all of the pieces together before you begin assembly. I also recommend starting with the arrow a little long, and shaving off a quarter inch or even eighth of an inch at a time until you hit your ideal arrow weight.
Step 4 – Put it all together
The great part about building arrows this way is it allows YOU to shape the arrow to your specifications. Be as specific as you want. Be as detailed as you want. And know that when you put it all together, you are shooting the arrow of your choosing instead of just hoping for the best from whatever was on the shelf.