Gone are the days where I could walk into a bow shop, tell them my draw weight and length, and they’d whip me up a dozen arrows in no time. As an unsophisticated compound shooter, that was all I needed. Mind you I am not saying that all compound shooters are unsophisticated, just that I was not too educated, and very willing to accept whatever the guy behind the counter told me I needed. It didn’t always look perfect to me, but it did the trick.
That approach might not work with a traditional bow. The shape of the riser and shelf (if you have one), the efficiency of the bow (how well does draw weight translate into limb speed and therefore force on the arrow, point weight (tradbow hunters tend to favour heavier weights up front than most standard spine charts take into account), and so forth, all influence what the right arrow is for your bow.
Some bow shop staff are knowledgeable and experienced with tradbows, I ran across one who nailed the spine just right for my selfbow, others enter terra incognita as soon as the bow does not have wheels, or the tip weight is not 100 grains.
When I say “arrow building” that sounds a lot more involved than it is. It’s not like I am finding natural materials, wood and feathers, and tendon and pine pitch, and putting them all together, like in the old days, and I’m not even buying blank shafts and fletching my own (for now). When I say “building” I mean figuring out spine, selecting a broadhead, thinking about tip weight versus arrow weight, front-of-centre (FOC), length, etcetera.
After a lot of agonizing, reading, and searching, having collected enough, sometimes contradicting information to make my head spin, I had an epiphany. I asked myself the question: “What are you going to be using this arrow for?” and another one: “How far do you actually think you will be able to accurately shoot come hunting season?”
The second question answered the first. Hunting. Killing an animal. Deer-sized and up, not excluding elk and moose. And the second question wasn’t too hard to answer either. I got fairly proficient at 20 yards with my selfbow, but never shot much beyond that. So I figured that if I’d be able to shoot decent out to 30 yards by fall, I’d be one happy camper. If I could build an arrow that would allow me to aim on the animal (I tried instinctive for two year, it wasn’t pretty), I figured I would be in business. An arrow that heavy would also negate any issues with having to aim ridiculously low on animals at closer ranges or coming up with a string-walking plan (moving your arrow nock down on the string, to use for close up shots), an approach that in my case would certainly lead to picking the wrong nock in the heat of the moment.
Since my bow is fairly light, I probably draw about 48#, in order to kill an animal a big as a moose, I would need to stack the odds in my favour and pile on penetration-enhancing factors as much as I could. That meant a heavier arrow, higher FOC, a broadhead that will not bend or fall apart, and a smaller-diameter arrow. None of this “knowledge” comes from experience, just “stuff” I read, and that seemed to make sense.
Without some sort of reference, I would still have been in the dark about where to start. How heavy an arrow would give me the desired trajectory? Luckily I had two arrows left from my selfbow set-up. 550 grains in weight, with 150 grains tip and 100 grs brass insert, 29″ long, 500 spine. These gave me approximately a point-on of 25 yards, and at 30 yards, a hold right around a deer’s back would centre-punch it.
The problem was that the 500-spine arrows showed a bit weak (fletching visibly kicking left in flight). So I used the 3RiversArchery spine calculator to look at some alternatives (http://www.3riversarchery.com/dynamic-spine-arrow-calculator-from-3rivers-archery.html). In this online tool you enter some bow characteristics to calculate a dynamic spine number, and then you select from a big library of arrows which one you might want to try. By manipulating spine, length, tip and insert weight, nock weight and fletching type, you need to try to match the number calculated for the bow as closely as possible.
Since I wanted a smaller diameter arrow, I chose the Easton Axis Traditional, which uses 16 grs inserts. I wanted lots of weight up front, in a broadhead that is milled out of a single piece of steel, as pointy as feasible with the weight, and ended up selecting the Rocky Mountain Specialty Gear Cutthroat broadhead in 250 grains (http://www.rmsgear.com/cutthroat-cutthroat-screw-in.html). I started out with “standard” 3×5″ feather fletching, right helical, and a simple plastic nock. Manipulating the tool showed that I needed a 400-spine arrow at a little under 28″, to make the numbers match.
This would give me an arrow of 555 grs, a calculated arrow velocity of 168 fps, and a little over 22% FOC.
Fast forward a month or so: the arrow paper-tuned at 28″ (there is room for operator error in that observation, a topic for another blog post), weighed in at 558 grs, and chronographed at 160 fps. It indeed has a point-on of 25 yards, and at 30, if I point it at the back of a (foam) deer, it punches a hole right in the middle.
So far the the sun is shining in my arrow world. Soon the broadheads well come out, and one arrow will be sacrificed to bare-shaft tuning. Hopefully I will still be happy after that.