Burris Eliminator III - Manual (Page 7)

Technical Notes
What calibers will the scope accommodate?
Most commercially available cartridges that will work with the
scope are listed in the Cartridge List that comes with the scope.
For low velocity cartridges with high Drop Numbers, your rifle
must be able to shoot a projectile with 230 inches of drop or less
at 750 yards when zeroed at 100yards. Virtually all modern rifle
chamberings can do this. For hand loaders, here is a list (at the
bottom of the page) of sea level Ballistic Coefficients Minimum
Muzzle Velocity combinations that drop less than the maximum
230 inches when zeroed at 100 yards.
The minimum amount of drop the scope is capable of is 65 inches
which is a far flatter trajectory than any commercially available
ammunition at the time of this writing and allows a lot of room for
handloaders and developers to reach for flatter trajectories.
Extreme Range Shooting (Beyond 750 yards)
The factors that influence a bullet in flight at extreme range are
many and their relationships are complex. Ballistics software
programs are of great benefit to get you close, but nothing beats
firing five shot groups with the actual ammo at 750 yards to
provide you with the most precise information possible in order to
perfectly program your Eliminator III LaserScope.
If you intend to shoot at game at 1,000 yards and beyond, it
would be irresponsible to not confirm accuracy at range for your
entire shooting system. If you need to change Point of Impact
(POI) at a range beyond 750 yards, try changing your BC.
Increasing BC will raise your point of impact (POI). Consider
changing the scope Zero for small changes at extreme distance.
A click of elevation will only change the POI .125 inches at 100
yards. It will change the POI 1.25 inches at 1,000 yards. Note that
a click also changes the POI .94 inches at 750 yards.
For Those New To Shooting Beyond 750 Yards
Here are a few additional things to keep in mind:
1. High BC is much more important than high muzzle velocity
at long range. The concept of Point Blank Range uses a long
Zero distance and very high Muzzle Velocity (MV) to shoot flat
enough to stay within 3 or 4 inches of your aiming line of sight.
That technique breaks down somewhere around 350 yards. No
cartridge shoots flat enough at these longer distances to even
consider not compensating for drop. High BC bullets are
usually a little heavier and have a little lower MV than low BC
loads for the same caliber. The lower MV gives them a little
more arc and puts them at a disadvantage in point blank range
discussions. The Eliminator III LaserScope handles drop for you
better and quicker than you could enter the data into a computer.
At distances of 750 yards and longer, high BC bullets have
several important advantages:
a. Higher BCs will actually shoot flatter at extended ranges than
a low BC /high MV ones. This will, extend the range the scope
can compensate for the bullet’s drop.
b. The high BC bullet is also less affected by the wind. Even with
the solid knowledge of the effects of a 10 mph crosswind that
the scope provides, wind will be the limiting factor for field
accuracy. For example: a .30-06 -190 gr. bullet with a .6 BC
launched at 2,700 FPS has 74 inches of drift from a 10 MPH
crosswind at 1,000 yards. That is about a 1/3 of what a 125 gr
bullet with a .25 BC launched at 3,200 FPS has with its 193
inches of drift. Whatever your error in estimating average
crosswind, you will have only 1/3 as much error on the target.
A 150 gr. bullet with a .4 BC at 3,000 FPS will drift 110 inches.
That is about half as much as that .25 BC load. Varmint shooters
can expect similar results going from a .15 to a .20 BC.
c. High BC bullets also retain more energy to bring game down.
From the above combinations at 1,000 yards, the .6 BC bullet
hits with 877 Ft-Lb; the .4 BC with 470 Ft-Lb; and the .25 BC
has only 221 Ft-Lb. Go for those high BC bullets if you have not
already done so.
2. Use good ammo. Everything affects bullet flight at these
ranges. Once you find a load that shoots well in your rifle, buy
or reload a good quantity. Odds are you will need to buy
“premium” ammo or hand load very carefully. If you change
bullets, even to one of the same weight and manufacturer you
need to re-zero and re-verify at range. Even the lot number
could make a noticeable difference beyond 1,000 yards.
Bullets with dented or dinged points should be used for
fowling shots, close-in work and practice.
3. Practice shooting in crosswind conditions.
4. Consider getting and carrying a good wind/pressure gauge.
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