Archery Tips > Choosing a BowMost of the
bows today are fine pieces of equipment. Manufacturers have improved the bows to
a point where breakage is not a problem unless you are trying to shoot super
fast with light arrows. All of the bows, from the least expensive to the most
expensive will probably shoot more accurately than you. You need to look for
features that suit you and the way you are going to use the bow. Here are some
features to consider in your purchase.
Bow Length - The trend today is for very short bows. You have
to shoot a release aid with these bows and they won’t work for you if you have a
long draw. Longer bows tend to be more forgiving. Some may argue with that
statement, but look at the archers that shoot the indoor targets where they
don’t just shoot for bulls-eyes. They shoot for the x in the center of the
bulls-eye. The winners are shooting bows that are at least 48” long. Short bows
are handy in tight situations, like hunting from a blind.
Bow Weight - The trend is very light weight bows. A light bow
is nice if you are packing it all day on long hunts. Light bows tend to not be
as accurate as a heavier bow. Most target shooters use heavier bows and add
stabilizers. More mass is more stable. Check out target rifles. They all have
heavy barrels. More mass also absorbs vibrations better, although there are a
number of products on the market now that do a good job of absorbing vibrations.
Brace Height - This probably influences accuracy and speed
more than any other feature. Brace height is the distance from the string to the
grip of the bow. A lower brace height gives a longer power stroke so the arrow
absorbs more energy and is faster. A low brace height also keeps the arrow on
the string longer so any irregularity in your form has more of an effect on the
arrow. Bows with a brace height below 7” tend to be a little tricky to shoot for
hunting.
Cams - The larger aggressive cams give more speed. They also
are harder to draw. There is not much difference in drawing a 70 lb. smooth cam
and a 60 lb aggressive cam. Arrow speed will also be similar. You can’t get more
out of a bow that you put into it.
One or Two Cams - Throw out the advertising hype and they
both do the same thing. Timing on an aggressive 2 cam bow is critical. Timing
isn’t near as critical on a soft 2 cam bow. Timing is the roll over of the cams.
They need to roll over at the same time. The nocking point will travel up or
down if one cam rolls over before the other. The nocking point will move more
with a radical cam with big lobes. Timing is not much of a problem with the
newer 1 cam bows so they can have aggressive cams. There was nocking point
movement on the early 1 cam bows. You also can have nocking point movement with
a 1 cam bow because the nocking point is not in the center of the string, like
on a 2 cam. You have twice as much string above the nocking point as below
because the string goes over the idler wheel and back down to the cam. String
stretch will move the nocking point. How much string stretch you get depends on
the string material. Newer bow string materials don’t stretch much after a few
hundred shots.
Bow Draw Weight - Today’s 50 lb bows will kill just about any
animal you will hunt in North America. Don’t get a heavier bow weight than you
need. You should be able to draw the bow straight back without raising the bow
or having to put a lot of effort into it. You need to be able to draw a bow in
slow motion after you have been sitting on a stand in cold weather for several
hours.
Draw Length - Most people today have too long of draw length.
They try to pick up speed by increasing the draw length. That causes tension in
the muscles which reduces accuracy and causes target panic. You should be
comfortable at anchor when pulling into the wall. That is especially true with
the short valleys on bows today. Creep just a little while you are aiming and
you are out of the valley and holding the peak weight of the bow. That can cause
you to trigger the arrow and hopefully it doesn’t fly into the next county.
INFLUENCES ON SPEED
Speed is based on the stored energy of the bow and arrow
weight. Some bow features store more energy than others. Here is list of the
items that control speed and the approximate speed you can gain.
-
Peak Weight - A change of 5 lbs. of peak weight is equal
to about 10 f.p.s.
-
Draw Length - An inch change of draw length is equal to
about 10 f.p.s.
-
Arrow Weight - A change of 25 grains of arrow weight will
equal about 5 f.p.s.
-
Brace Height - An inch change in brace height is equal to
about 5 - 10 f.p.s.
These are rough estimates because many times if you change
one you have to change something else. For example, increase the draw weight or
draw length and you might have to shoot a stiffer arrow, which is heavier. You
also get diminishing return as you reach the extreme. Increasing the draw weight
from 85 to 90 lbs will not have as much affect as increasing it from 45 - 50 lbs
because the percentage of change.
In addition to this, some bows use the stored energy more
efficiently. Needle bearings in the cams will reduce friction and increase
speed. Limb design can also make a difference in efficiency. Others like the
type of cable slide, string material, peep sight, etc., also make a difference.
ADVERTISED SPEEDS
Manufactures advertise AMO speed and IBO speed. AMO is the
Archery Manufactures and Merchants Organization. IBO is one of the largest 3-D
shoot organizations. AMO speed is with a 540 grain arrow shot from a 60 lb. bow
with a 30” draw. IBO uses a 70 lb. bow and a 350 grain arrow because that is the
lightest arrow and heaviest bow allowed in their shoots. The speeds the
manufacture list are likely to be faster than you will shoot. Most bows come
with an adjustable draw length. 30” draw may be obtained with 3 different cams
that cover 3” of draw adjustment. Those 30” draw lengths will all have different
speeds. Some manufacture’s draw lengths run long so what they call 30” may
actually be 30 3/4”. That will increase the speed rating by up to 5 f.p.s. In
addition to all of that, many test their bows with no nocking point on the
string because that additional weight on the string will reduce speed by a
couple of feet per second. Use the manufacture’s rating as a rough guide. They
may vary by more than 8 f.p.s. from an independent test. 5 f.p.s. would not be
noticeable to anyone shooting a bow. It generally takes 10 - 20 f.p.s. to make
any noticeable difference. You can figure bows that are within 5 f.p.s. speed
rating are equal because of the differences in their testing. |