Arrow Speeds
Without a Chronograph
By:
Vaughn Rader, Field Editor
Not
all of us can own a chronograph so if you are wondering approx.
how fast your bow is shooting, here is a guide that can get you in
the ballpark. You can then figure your Kinetic Energy if you know
you arrow speed and the weight of you arrows in grains.
Arrow speed without a chronograph: You can approximate your arrow
speed using the following simple table. First, shoot a group with
your bow at a target from 20 yards using your 20 yard pin. Mark
the center of your group. Next, shoot from 40 yards, still using
your 20 yard pin and aiming at the same point on the target as
before. Mark the center of this group, and measure the distance
between the two marks. Refer to the table for your arrow speed.
Approximate Arrow Speed (fps) Spread between 20 & 40 yard
groups (inches)
220 =28.7
240 =24.2
260 =20.6
280 =17.7
300 =15.5
320 =13.6
330 =12.8
Doing the calculations: The following formula
should be used to calculate your arrow's kinetic energy (KE). Use
finished arrow weight expressed in grains and arrow speed in feet
per second.
KE = (arrow weight)/450 X (arrow speed)2
Here is what is recommended as the absolute minimum levels of
Kinetic Energy for a given animal. Of course, extra energy is
useless if you don't put the arrow in the vital areas.
KE Hunting
Usage
< 25 ft./lbs. Small Game
25-41 ft./lbs. Medium Game (deer, antelope, etc.)
42-65 ft./lbs. Large Game (elk, black bear, wild boar, etc.)
> 65 ft./lbs. Toughest Game (Cape Buffalo, Grizzly, etc.)
This chart is for a fixed blade broadhead. It is recommended that
you use at least 55 ft./lbs. for deer sized game with mechanical
broadheads and 60 ft./lbs. for elk sized game. It is an absolute
must that your broadheads are sharp. If you shoot the blades even
once, replace them or resharpen them before shooting them at
another animal. Good Luck and Good Shooting!
Vaughn Rader
Field Editor
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