reading the wind and distance to target, the slope angle of
fire is one of the least understood and equally important
variables of long range shooting. Whether shooting up or down
at a target, the bullet will impact high due to the cause and
effects of gravity.
The latest aid for snipers
and practical field shooters who must engage elevated or
depressed targets, the Angle Cosine Indicator (ACI) still
requires the shooter (or, more likely, his spotter/observer)
to perform a calculation. The ACI attaches to the shooter's
scope, minimizing the possibility of breaking cheek-weld and
losing sight of the target.
constructed, the ACI is made from aircraft grade aluminum and
is available in anodized olive drab or black. The ACI is the design of Ward Brien,
former U.S. military servicemen with design contributions by
his partner Ping Lee.
When properly mounted and
the rifle is elevated or depressed, the ACI (with the cosign
numbers in five degree increments) bypasses the angle and,
instead, indicates the corresponding cosine number of the
angle of the elevation or depression. The shooter or his
observer/spotter need only multiply the actual range by the
cosine number to get the adjusted range. Having done so, the
shooter adjusts the elevation on his scope and engages the
target. If he has done everything correctly, including
compensating for wind (which works along the actual distance
of the shot), the shot should be dead on target.
Use the ACI!
It's quick, easy to use, easy to install,
extremely rugged and unaffected by weather.
NOTE: Mounting requires the use of a claw-type scope ring,
such as a Leupold MK IV or others.
Ring not included.