5
TBR
™
(TRUE BALLISTIC RANGE
™
): ARCHERY
40
Ya
rds (37 Meters) (line of sight) at a 40° Incline
Aim as if th
e target is 34 yard
s (31 meters) away
BOW GROUP DATA
Bow
Group
Initial Arrow
Velocity
(feet/meter
per second)
Drop from
20 yard
(18 meter) pin
at 40 yards
(37 meters)
Typical Bow Description
A
Less than 215 ft/
Less than 66 m
30 or more inches/
76 or more cm
Older bows shooting aluminum arrows and newer
bows set at draw weights below 50 lb (23 kg)
B
215 to 250 ft/
66 to 76 m
20 to 30 inches/
51 to 76 cm
Quality, newer bows shooting carbon arrows at
50-65 lb (23-29 kg) draw weight
C
250 or moreft/
76 m or more
Less than 20 inches/
Less then 51 cm
Fast bows with draw weights in excess of
65 lb (29 kg)
FUNCTION 14: BOW BALLISTICS GROUP
This mode, when activated, works with TBR
to provide the correct ballistics range for
arrows. To activate, move through the
Quick Set Rotary Menu by pressing
MODE
and select BOW by pressing SET.
Selecting the BOW Mode automatically
deactivates the Rifle Mode. The displayed
range represents the ballistically equivalent horizontal distance
to the target. It incorporates three different groups (A, B, or C)
depending on the particular arrow drop. You must choose one of
the three
groups, based on your bow and arrow selection. Only one
group can be selected
at a time. Selecting a new group deactivates
all other groups. Most importantly,
using BOW effectively means to
Practice, Practice, Practice. Anytime you handle a firearm or bow,
you are ultimately responsible for your projectile.
For best results, measure the drop of your arrow at 40 yards
(37 meters) when using your 20 yard (18 meter) aiming point.
1. Set up a small target point such as a two-inch circle of paper
high on a large, safe background, such as a stack of bales
backed by a solid backstop. Be sure to allow for three feet or
more of drop to avoid arrow damage.
2. Shoot 2 or 3 arrows at the target from 40 yards (37 meters),
using your 20 yard (18 meter) pin on the small target.
3. Measure the distance from the small target to the center
of the group of arrows.
4. Select your TBR bow group from the “Drop from 20 yard
(18 meter) pin at 40 yards (37 meters)” column above.
Initial velocity should only be used if an arrow speed chronograph
measurement has been obtained. Manufacturer’s published data
such as IBO speed is based on standard draw length and weight that
is likely to vary with your bow, therefore the actual performance
may not be the same.
FUNCTION 15: SEVEN RIFLE BALLISTICS GROUPS
TBR includes ballistics settings for seven cartridge
groups specifically formulated for the three
functions of TBR, which are displayed as
A, B, C, AB, AC, BC, and ABC. For example,
if your cartridge group is in Group A, the
return in Function 15 will account for the
shot angle and provide the proper distance for
holdover purposes (see Cartridge Table chart on page 6).
You must choose one of the seven groups, based on your cartridge
and ballistics information. TBR performance groups organize load
performance in a way that generally provides less than
2.5 inches (6.35 cm) (1/2 minute of angle) of error in aiming out
to 500 yards (457 meters). The cartridge table shows a common
assortment of factory loads organized in their TBR performance
groups. If you are shooting a similar bullet weight and muzzle
velocity that falls into the provided selections, you can use that
mode with full confidence.
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