How Fast Is Too Fast?
October 28, 2010
Technological innovations over the past three years have produced huge increases in arrow speed, and it's now common to find bows that produce IBO speeds greater than 330 -- or even 350 -- feet per second.
When using fixed-blade heads, you will have a harder time controlling a fast arrow than a person using mechanical heads. However, compact fixed-blade heads plane less than larger ones.
While I don't question these bows' ability to handle the vibration and deliver a straight flying arrow, I do question the ability of most bowhunters to harness the newfound speed in a constructive way. From a pure accuracy standpoint, there is definitely a threshold when fast becomes too fast, and that's something to consider before buying a new bullet bow.
The Benefits Of Arrow Speed
Shot placement is a game of inches. An inch too low and you hit the brisket instead of the heart. A friend did that last year while I was filming his hunt. We lost the buck. An inch too high and you're in "no man's land" instead of hitting the top of the lungs. In either case, instead of a short drag back to the truck, you're in for a long and likely disappointing tracking session.
Anything that will improve accuracy in the field even slightly is worth pursuing, and shooting a faster arrow can certainly do this. You may not think a few extra yards of wiggle room is a big deal, but it's these small things that add up to make a big difference.
Put yourself in this position: A buck steps out of the brush at a spot you didn't expect. In a moment, he'll be through a narrow shooting lane and gone. You haven't pre-scouted the distance but quickly estimate it at 30 yards. You draw your bow, hold your 30-yard pin right on the middle of his chest and make what you believe to be a perfect shot.
Assuming you generate average arrow speed (something around 260 fps), you'll hit the buck in the vitals if he's actually standing anywhere between 23.3 and 34.5 yards away (a window that is 11.2 yards wide).
Now, suppose you shoot an arrow that travels at 320 fps. Your window increases to include all actual distances from zero to 36.5 yards (a window that's 36.5 yards wide). An arrow speed increase of 60 fps increases your margin for error on 30-yard shots by more than 300 percent. Clearly, that extra speed can make a huge difference in the outcome of the hunt.
And that added velocity becomes even more precious as you stretch the distance out to 40 yards. Considering that, it is hard to make any kind of argument against more arrow speed -- at least on the surface. But there is more to consider.
Too Much Of A Good Thing
Now that I've made the case for a fast arrow, let's consider the downside. There is definitely a speed limit, and if you go over it, you'll no longer enjoy the benefits increased arrow speed is supposed to offer. Arrow speed is only beneficial if it doesn't make you less accurate at known distances. In other words, if you are standing on the range at 40 yards and can't shoot a fast bow and light arrow as accurately as you can a slower bow and heavier arrow -- especially when equipped with broadheads -- that speed is a liability; not an asset.
Your personal speed limit depends on the type of equipment you use, starting with broadheads. Fixed-blade heads will wind plane to varying degrees and steer an arrow off course if you shoot them from a poorly tuned bow, into a crosswind or if you make a rough release.
And the faster the arrow, the more pronounced this planing becomes. Even with today's small profile, fixed-blade heads, most experts recommend a maximum arrow speed of 260-270 fps. Beyond that, broadhead planing becomes problematic for all but the very best archers.
Today's fastest bows are awesome in their ability to deliver speed. But just because the bow is capable of producing it doesn't mean you are capable of harnessing it accurately.
When using mechanical broadheads, planing isn't as much of an issue. Accuracy with mechanical heads can, and often does, rival that of a field point. However, even mechanical heads must be perfectly aligned, and the bow properly tuned, to accurately handle high arrow speeds.
Some mechanical broadheads will cause wind planing if they have a sizeable amount of exposed blade. I have even seen very noticeable amounts of wind planing on arrows carrying only field points, because the shaft itself causes the arrow to plane if it doesn't exit the bow perfectly straight.
Now, let's consider vibration, which really increases as you shoot light arrows from a high-energy bow. Easton produced a super slow motion video several years back that showed the devastating effects of vibration on the accessories of a bow shooting a light arrow. The rest and sight flapped around as if they were attached with Silly Putty. Such abuse will eventually tear your accessories apart, if not the bow itself.
Until pieces start hitting the ground, it is difficult to know exactly when you are pushing your rig too hard. Personally, I have always liked finished arrow weights of at least six grains per pound of draw force. So, for a 70-pound bow, your arrow would have to weigh at least 420 grains.
Shooting Form Speed Limit
One of the ways bow manufacturers have made today's bows faster is by reducing brace height. Some of these popular bows now have brace heights as low as 5.5 inches. While it is debatable whether a lower brace height makes a bow less forgiving, there is definitely some logic to it. The lower the brace height, the longer the arrow stays on the string, giving the shooter more time to negatively impact accuracy with poor form.
If you have excellent shooting form and maintain it through regular practice, you can shoot a bow with a low brace height accurately. You have to hold your follow-through a little longer and keep your bow hand relaxed until the arrow hits the target. However, most bowhunters don't practice nearly enough. Therefore, it makes sense for the majority to shoot a bow that's designed to get the arrow off the string as quickly as possible.
If you're an accomplished archer, you can get away with a brace height down in the six-inch range. But if you don't have the time or desire to really master the sport, stick with the most forgiving designs: bows with brace heights of seven inches or more. Next time you compare bows, make sure to compare brace
heights and get only as much bow as you can accurately handle.
The Final Analysis
While there's no arguing their popularity and appeal, today's fastest bows aren't for everyone. Yes, they will work great for those who practice regularly. But everyone else will be better off with a bow having a higher brace height of at least seven inches -- even higher would be better.
I suppose if you are going to hunt antelope in the wide-open plains of Wyoming, a super light arrow flying 325 fps would be an asset. But in such open settings, surprise shots are rare. You will normally have time to use your range finder, so arrow speed becomes a bit less important. Personally, I can't see a good enough reason to put my accessories (and thus my hunt) in jeopardy by shooting an arrow weighing less than six grains per pound of draw force.
Stick with medium weight arrows and only as much bow as you can handle accurately and you will do just fine.