Speed is a factor in kinetic energy and momentum, but ultra-light arrows lose it quickly downrange. On the other hand, super-heavy arrows can make a bow difficult to tune for accuracy. (Photo courtesy of Mathews)
September 28, 2020
By Tony Hansen
Speed kills. Until it doesn’t.
For a lot of years, bow manufacturers (in response to the demand of bowhunters) focused much of their efforts on building compounds that could deliver blistering speeds. Each new model was in a race to see who could build the fastest bow. The premise seemed to make sense. Faster arrows would take much of the “arch” out of archery, and this happened to pair quite well with the growing interest in long-range shooting. A fast bow delivers a flat arrow at greater distances.
Arrow companies decided to jump on board the speed train. Their part was delivering ultra-light, thin-walled carbon shafts that retained minimal energy downrange but zipped there in a hurry.
It was around this time that broadhead manufacturers started to unveil a new type of broadhead: the mega-cutting mechanical. The concept there also seemed logical. If a small hole is good, a great big hole is even better. And with bows delivering such high speeds, surely they would deliver enough energy to push that 2-inch head through a deer with ease, right? Turns out, maybe not.
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Today, the trend is much different. Thanks in part to some influential YouTubers and social media chatter, the popular movement is toward ultra-heavy arrows delivering massive amounts of energy and broadheads that feature uber-strong steel construction with single-bevel blades. These 650-grain total arrow weight setups focus heavily on front-of-center (FOC) weight distribution, mega-weight broadheads (think 150 grains plus) and overall arrow weights nearly double what was common just a few years ago.
The science (particularly the laws of physics) back up the intentions here. These arrow and broadhead setups seem to have the punch to zip through a Buick. The downside? Extreme FOC arrows with ultra-high overall weight can be a devil to tune for many
The takeaway? Both trends, in this bowhunter’s opinion, have been taken a bit too far and create more problems than they solve. The solution? Well, I feel some good old-fashioned compromise is in order.
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The 125-grain Wasp Havalon has a 1 3/16-inch cutting diameter, which provides adequate wound-cavity width without unduly hampering penetration. (Photo courtesy of Wasp) Happy Medium I am not, nor have I ever been, a “speed guy.” I’ve never really worried too much about a bow’s IBO rating. That’s only partly because, much of the time, advertised IBO speeds seem to be based on a set of mythical circumstances and are something I’ve not been able to duplicate on my backyard range. It’s mostly because I don’t need nor want a super-fast arrow. I need an arrow that will pass through a buck when I shoot him in the ribs and one that gives me a fighting chance if I hit part of the shoulder bone. Super-fast bows (and arrow setups) have also proven to be squirrely in tuning, particularly with broadheads.
That said, speed does factor into the kinetic energy and momentum equation quite a bit and, in general, a bow that delivers a faster arrow is going to deliver more downrange energy than a slower bow. I can appreciate that, but speed for speed’s sake makes little sense.
For arrows, I look at something in the neighborhood of 9 grains per inch. I also add the heaviest insert that’s available.
With broadheads, I take a similar middle-ground approach. I understand the attraction of a huge cutting surface when running an arrow through a deer. But, again, the laws of physics tell us that doing so is going to require a whole lot of energy. That means we likely need more speed and less arrow weight, which seems to be counterproductive if the goal is to drive a really big broadhead through a deer. Instead, I lean toward a solid, fixed-blade broadhead that is super sharp and super strong.
I’ve settled on 125-grain heads in my happy medium setup. There are two that I like a lot: the Wasp Havalon and the Woodsman offered by 3Rivers Archery. If I were better with a sharpening stone, the Woodsman would probably get the nod as my favorite. But I’m not, thus the replaceable blades of the Havalon are highly attractive.
Weighing 125 to 200 grains, the Woodsman Elite is machined from a solid piece of steel for strength. The heavier versions provide an easy way to increase overall arrow weight. (Photo courtesy of 3Rivers Archery) End Result Taking all that into account, here’s the combination I’ve come up with. I currently shoot Victory Archery VAP shafts in the 250 spine, which come in at 9.8 grains per inch. I have a 29-inch draw length and cut my arrows at 29.5 inches. That gives me a bare arrow weight of 289.1 grains. Add the 125-grain head on the front, and the weight goes to 414.1. I use the VAP Shok steel insert, which adds 95 grains for a total of 509.1. The nock and vanes add another 40 grains (depending on the nock I choose). That puts me very close to 550 grains.
The happy medium weight is a range of 550 to 600 grains. In my experience, arrows in this range will be the easiest to tune and will deliver moderately flat flight out to, say, 45 yards depending on bow speed. This is where speed becomes a factor. I shoot a Mathews VXR 28, which has an IBO rating of 344 fps. IBO speed is recorded using a 350-grain arrow. You’ll lose roughly 1 fps per additional 5 grains of arrow weight. My arrow is 206 grains above IBO weight and gets speeds of about 310 fps.
Whether you subscribe to the school of momentum or the school of kinetic energy, arrow speed has an impact on both formulas. The VXR is not the fastest bow available, and it’s certainly not the slowest. If you’re working with a slower bow and shooting the same 550- to 600-grain arrow, you will see a reduction in momentum and kinetic energy.
Although an arrow and broadhead combination that attains a high velocity will flatten trajectory for long shots, it may not result in adequate penetration once it reaches the target. (Photo courtesy of Mathews) Final Tweaks A 600-grain arrow is, in my experience, pretty close to ideal for most setups. It’s important to do some math and know the speed your bow can deliver an arrow of that weight. It may not do you much good to go that heavy if the arrow quickly loses kinetic energy and momentum because the bow isn’t able to push it fast enough. That said, most of today’s modern compounds can do so with relative ease.
To increase my overall weight to 600 grains, I could experiment with several options. The Woodsman is available in weights up to 200 grains. I could also opt to install tube weights. They weigh about 8 grains per inch, and I could trim to obtain the weight desired.
The magic comes in the tweaking. I could certainly put a heavier broadhead on the front of the arrow and boost overall arrow weight and FOC. This would reduce the arrow speed somewhat but likely increase the kinetic energy and momentum numbers. But experience also has shown that I’ll start to have tuning issues. They can absolutely be cured, but that takes time and knowledge. That all is to say, super-heavy arrows aren’t bad by any means. There are drawbacks to them, though, and most average bowhunters will likely struggle to get them tuned.
Thankfully, more bowhunters are starting to place more emphasis on momentum and arrow penetration than pure speed. This is a very good thing, but too much of a good thing can be problematic. Shooting a 650-grain or heavier arrow will undoubtedly lead to more pass-throughs, less issues with bone hits and increased kills. However, you really have to know what you’re doing to get those arrows to fly and group consistently. It’s an art that many bowhunters simply don’t have the time or experience to master. There’s no shame in that. I count myself as one of them, and believe a happy medium will deliver excellent results on the range and in the field.
