Burris Eliminator III - Manual (Page 4)

4
Button B1: (Left)
Generally, Advance
with Save Through
Selection Process or
Modes.
Button B2: (Up)
Generally, Increase
Values.
Button B4: (Right)
Generally, Exit with Save.
Button B3: (Down)
Generally, Decreases
Values.
Sea Level Change/K Ft
DROP BC Drop (-) BC (+)
132 0.41 -2.1 .016
Here is the Selection and Setup process:
First decision - What units do you want to work in, Yards or
Meters? Y/M
Next, Info Needed – You need to know the bullet drop, in inches,
at 750 yards when zeroed at 100 yards. This figure will be your
Drop Number. You will also need to know your bullet’s Ballistic
Coefficient (BC). We use the commonly available G1 BCs. What
you see published in advertisements and loading manuals is
assumed to be G1 unless stated otherwise. See our website for
more explanation.
There are several ways to determine your correct Drop Number
and BC:
1. For factory loads, the Cartridge List that came with your scope
will show the sea level drop number and BC for most of the
currently available factory ammo.
2. Factory ammo web sites sometimes provide this information.
3. Hand loading manuals always provide bullet BC data.
4. The drop number and or BC may appear on the ammo box.
5. Ballistics Software Programs can provide this info.
6. Measure your actual bullet drop at 750 yards, when sighted
in at 100 yards.
7. Use the Cartridge List to estimate your drop number and BC by
finding similar loads.
8. Check the Burris website: www.burrisoptics.com.
Note: the correct Drop Number is best determined by actually
measuring your drop. All other methods provide approximate
numbers that will get you “on paper” at 750 yards — typically
correct ±3 inches at that distance. Then, just correct the few
inches needed from there. See “Verifying your drop-BC Table
Selection” below. The BC published in the Cartridge List is a sea
level value. The section on Altitude Compensation further
explains how to adjust at elevations other than sea level.
NOTE:
1. No matter what units you chose to work in (yards or meters),
the Ballistic Tables are selected based on drop at 750 Yards
when zeroed at 100 yards.
2. See the altitude compensation section of the manual to
correct your initial setting Drop and BC values.
Your selected unit, Drop Number and BC are combined to give
you a setup Table Number. We put a 1 after the unit letter, then the
Drop Number (using three digits), followed by the BC (without the
decimal). For example:
A Table selection for Yards, with a 92 in drop at 750 Y and a BC
of .47 would combine like this: Y1 092 47
A Table for Meters, with a 132 in drop at 750 Y and a BC of .53
would combine like this: M1 132 53
Now you need to set the scope to use the Table you selected.
Altitude Compensation:
Your bullet’s flight will be affected by air pressure, which is primarily
determined by altitude. Both the drop at 750 and the BC number
need to be corrected for altitude changes of more than 1000 feet.
The Drop and BC numbers in the Cartridge List are sea level values.
There is a compensation number for 750 yard Drop and for BC for
every 1000 ft of elevation change (Change/K Ft.). As altitude
increases and air gets thinner, the effective BC gets larger while the
effective Drop Number gets smaller.
Determining Your Altitude-Adjusted Drop Number and BC
This example shows how to adjust a Sea Level Drop Number of
132 and a BC of .41 to an altitude of 4,500 feet:
Drop Number
Altitude (4.5) x Change/K Ft. (-2.1) = -9.45
Altitude Adjusted DROP Number: 132 - 9 = 123
BC Number
Altitude (4.5) x Change/K Ft. (.016) = .072
Altitude Adjusted BC: .41 + .07 = .48
Altitude Adjusted Starting Point = 1 123 and 48
How to set the scope to use the selected Table
There are four arrows on the Set-up button on the left of the
scope. These buttons are basically used only for Scope Set-up.
Enter Set-up Mode
1. Push the On/Range button to turn on the scope. Push the
On/Range Button once more to get the four dashes (_ _ _ _) or
a range display in the range area.
2. Push and hold the B1 (Left Arrow) button first, then also press
one of the On/Range buttons and hold them both down
simultaneously for 6 seconds. Release the buttons when the
display changes. This is called “Set-Up” Mode. The first number
that appears for two seconds is the firmware version. Next, the
display shows the currently selected Y (Yards) or M (Meters)
and previously selected Table. On new scopes the reading will
be “Y 1137 42” which is the factory-shipped table. If another
Table has been previously selected, the designation for that
table is displayed.