Speed Up Your Bow
By Brandon Ray
Jul 20, 2006, 06:55
Follow these simple suggestions to add extra fps to your bowhunting rig.
|Controlled Speed has it's rewards.
It used to be that extra arrow speed created almost
as many problems as it solved in a hunting bow. The boosted feet per
second (fps) created tighter pin gaps. That was good. However, boosted
speed created problems when steering broadheads. That was bad. Added
speed also allowed slightly more room for error in yardage estimation.
That was good. But extra zip from an ultralight arrow also created more
vibration and noise in the bow. That was bad. A lighter arrow could
even help extend a shooter's effective shooting range. That was good.
But if the arrow was too light, kinetic energy petered out at long
distances and penetration suffered. That was bad.
I think most of those potential problems are less
serious these days due to improved equipment. Super-short, fixed blade
broadheads with 1-inch cutting diameters fly like darts out of fast
bows. Mechanical broadheads do the same. The extra noise and potential
vibration created by a lighter arrow can be remedied with an assortment
of sound dampening devices on limbs, strings, cables, and stabilizers.
Today, a bow that shoots fast can still be very quiet.
|And, speed kills
Controlled Speed is Good
Faster arrows are an obvious plus on western game
such as antelope or mule deer where shot distances of 40 and 50 yards
are the norm, but don't overlook the benefits of boosted speed for
whitetails. Even in the East, where most treestands hang in thick
timber, you'll occasionally face a target at longer range. For example,
a buck that feeds in the center of a small food plot when your stand
hangs at the wood's edge. He might be 35 or 45 yards away. About twice
the distance of the average treestand shot at a whitetail. Or a deer
that wanders down an old logging road carved through the trees. Last
fall, in Illinois, I used a 60 pound BowTech Allegiance to thump a wary
doe wandering down an old road in the thick woods. That shot was 42
yards. Forty yard shots happen east of the Mississippi, too!
I appreciate extra speed no matter what game I hunt.
I shoot a modest draw weight, lately right at 60 pounds, and my draw
length is roughly 28 inches. A short draw length and a modest draw
weight don't exactly ring of ramped up speed. But by following a few
simple steps, it's possible to rev up any bow.
A reduction in arrow or point weight is an easy way
to increase speed. The exact number of fps gained will vary from bow to
bow, but on average you can expect to gain 1-2 fps for every 5 grain
reduction in finished arrow weight. Simply put, a lighter arrow is a
Over the last few seasons, even though I've hunted
with several different kinds of arrow shafts, different size shafts and
assorted makes and weights of broadheads, my finished arrow weight has
typically been in the 360 to 420 grain range. That comes to roughly six
to seven grains per pound of draw weight. In my experience, that's a
good compromise in lighter weight for faster speed while still
maintaining enough arrow weight to produce good penetration on
deer-sized targets, even at longer distances.
Given these weights of arrows, shot at speeds from
250 to 280 fps, my bow rigs usually generate 50 to 60 foot pounds of
kinetic energy. In my experience, that amount of energy is plenty for
game like pronghorns, whitetails, mule deer, black bear and feral hogs.
I shot a similar rig in Africa to shoot even larger animals like kudu,
waterbuck and red hartebeest. In my experience, this is a borderline
rig for best performance from mechanical broadheads, where more kinetic
energy would be better. So I opt for sweet-shooting, compact
fixed-blade designs instead of open-on-impact broadheads no matter what
Check arrow selection charts and you'll see several
shaft options for your specific draw weight and arrow length. If
accelerated speed is your goal choose a shaft size on the lighter end
of those options. Gold Tip even has a nifty calculator on their web
site that automatically figures the finished weight of your arrow
depending on length, fletching, shaft size and components.
Fletching options provide another way to shave
finished weight. Shooting feathers instead of vanes will add speed at
launch, although feathers slow down a bit at 40-plus yards compared to
vanes. One four inch plastic vane weighs about 8-12 grains depending on
the brand, while one four inch feather weighs 2.5 grains. Recently, I
weighed three four inch vanes before fletching a shaft. Each weighed 9
grains (27 grains total). When I switched from three, four inch vanes
on my arrow to three, four inch feathers (7.5 grains total) I reduced
arrow weight by 19.5 grains. On my current setup it's a difference of
about 4 fps of arrow speed at typical hunting distances from vanes to
Switching to a lighter broadhead will also boost
speed. For example, a switch from 125 grain broadheads to lighter 100
grain heads will increase speed by roughly 5 fps. Similarly, switching
from 100 grain points to 85 grain points boosts my speed by another 4
fps. Lightweight broadheads, something from 80 to 100 grains, are
usually the best mate for a lightweight shaft to provide proper
front-of-center balance. When shooting lighter arrows for deer-sized
game I'm a big fan of the new generation of super-short, fixed-blade
broadheads for best odds of deep penetration. Today's market has
numerous compact, fixed-blade broadheads with a cutting diameter of 1
1/8-inches or 1-inch. These are an excellent choice for bowhunters
toting bows shooting 260 fps or faster who demand dart-like arrow
flight, but don't want to use mechanicals.
String things are a common road block to a
potentially fast rig. There are many factors other than just the string
accessory that effect speed differently such as cam design, draw
length, arrow weight, release type, etc. Also, different brands of
string silencers, for instance, can give different velocity changes.
However, as a general rule, a regular-sized peep sight will cost most
setups 4-7 fps.
String silencers will generally lose 5-8 fps or more
(these are very dependent on the silencer design as well as where they
are positioned in the string. The closer to the cam you can position
the silencer, the less speed you will lose as a rule.) A brass nock
means a speed loss of 2-4 fps. Rubber peep tubing robs 6-10 fps. Rubber
e-buttons cause a speed loss of 2 fps each. And a string loop, without
brass nocks, causes a speed loss of 1-3 fps.
To keep things simple think of it this way. Anything
you add to the bowstring; peep, peep sight alignment hose, string
silencers, extra wraps of serving, brass nock point, string loop,
eliminator buttons, kisser button, etc. will decrease arrow speed. Of
course there should be a balance between adding the items you truly
need to increase accuracy and squeezing out every drop of speed
possible from your setup while keeping it quiet. Even the material used
to make the bowstring can change speed. Consult with custom string
makers such as Winner's Choice on string materials that could
potentially boost your arrow speed.
Other ways to increase speed include increasing your
draw length, although a draw length that fits properly is more
important than the few fps you gain by increasing it. Also, an increase
in draw weight will increase speed. Speed increases from poundage
varies from bow to bow, but roughly 1-3 fps are gained for each pound
of draw weight added. Aggressive cams are faster than soft cams.
Everything else equal, a bow with 65 % let-off is faster than the same
bow with 80 % let-off. And bows with a shorter brace height, something
under 7-inches, are faster, but less forgiving than bows with a longer
By combining some or all of these things it's easy
to crank-up arrow speed for a faster, flatter shooting arrow. And if
you can control that extra speed and maintain pinpoint accuracy, even
with broadheads, that's always a good thing.
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