Making a shot on a ram at 400 yards or a coyote in the next zip code requires a unique skill set and special tools. Beyond superior vision, patience, a steady hand, and an accurate rifle, shooting ultra-long-range is all about having the right scope. A scope like a Burris Black Diamond.Engineered specifically for the rigors of long range shooting, Burris started with a 30mm tube then added multi-coated optics precision-ground from superior glass. The end product is a scope that delivers extraordinary sharpness, contrast and clarity that out-shines even high dollar European scopes.
The Right Tools For The Job
Ballistic PlexPrecision rangefinders, specialized rifles and more accurate ammunition have removed some of the variables in long-range shooting. However, with a basic crosshair reticle, calculating hold-over is a mix of art, science and just plain luck. Which is exactly why Burris developed the Ballistic Plex reticle. The key is the copyrighted lower vertical crosshair. With most common hunting cartridges, a shooter can use the reticle to compensate for bullet drop and aim dead-on at targets from 100 to 500 yards out. The need for hold-over guesstimation is eliminated.Using it is simple. Start by sighting-in your rifle at 100 or 200 yards at your scope’s highest magnification. Then, once you determine the distance to your target, select the appropriate ballistic line. Add slight hold-over or hold-under for in-between yardages and take the shot.
Burris has kept the Black Diamond’s length, weight, and mounting profile to a minumum. Other practical features like fingertip adjustable and resettable dials, up to 4 inches of eye relief, and convenient side parallax adjustments are a big plus when the pressure is on.
Forever Warranty – Protects Burris products from any defects in materials or workmanship — even if you are not the original owner. Burris will, at our option, repair or replace the item at no charge.
Unique Technical FeaturesThe outer tubes & internal components are extremely robust.The adjustment system is:- repeatable- steel on steel- with audible clicksDouble internal spring force. Every Burris scope has it.
Posi-Lock• Posi-Lock is a coil-spring assisted retractable steel post that firmly and & securely locks accuracy into place. • Once the reticle is zeroed, the covering tube (red) replaces the internal spring (green) & locks the inner tube in place. • All scopes have one spring that allows the adjustment of the reticle. Some of the competition competitors offer a double spring whereas the double spring is the STANDARD for all Burris products. • As an optional, it’s possible to have the special Posi-Lock system. Posi-Lock scopes remain perfectly zeroed year after year even during transportation.
In the closed position, the force of the spring is substituted by the force of the steel post on the internal tube of the scope.
On all rifle scopes:• Each scope is filled and purged at least 24 times with high quality, laboratory grade dry nitrogen. Each nitrogen cycle absorbs airborne and residual surface moisture that is evacuated from the scope• Every scope is individually recoil, water and fogproof tested • Burris uses specially made quad seals to provide double insurance against leakage
Recoil TestBurris scopes are subjected to extreme recoil testsAn impact machine is used to measure and duplicate the recoil pulse acceleration and duration.This machine has been calibrated and verified by an independent laboratory to replicate the wave frequencies and shock impulses that a scope is subjected to.
Waterproof TestAll Burris optics are proven to be absolutely waterproof.Each scope is submerged in water with a temperature of 50° C.The extremely hot water transfers its heat to the scope and the internal nitrogen expends 100% testing assures quality. Fog TestThe nitrogen contained in the scope is:• of high quality (ultra dry, laboratory grade nitrogen)• ultra pure• ultra cleanTo be sure that all airborne moisture and surfaces moisture within a scope is evacuated, testing consists of 24 cycles of • pressurizing the scope• subjecting it to a vacuumThe tests are both cost & time intensive
With the advent of laser rangefinders, more long range rifle designs, more accurate ammunition, more and more American sportsmen started pursuing long range marksman- ship. Vital to success in shooting at long distances is in how accurate one can judge hold-over. So Burris has created a couple of trajectory compensating scope reticles to aid hunters in dramatically increasing their long range accuracy.
Prior to the Ballistic Plex reticle, in 1999 Burris introduced the Ballistic Mil-DotTM reticle in a 6X-24X Signature Series® scope, primarily with the varmint hunter in mind. Although the Ballistic Mil-Dot was calibrated for flat shoot- ing varmint loads, it also closely matched many Magnum big game cartridges and was popular in both varmint and big game circles. Still, a considerable number of hunters asked for trajectory compensation in more moderate magni- fication scopes and for more traditional cartridges. Also paramount was simplicity and an uncluttered view.
In the year 2000, Burris introduced the Ballistic Plex reticle. Starting with a standard Plex reticle, two slight modifications were made. Most obvious is the addition of ballistic refer- ence lines to the lower vertical crosshair. Less obvious is the thickening of the outer section of the crosshair with a slight taper from the center to the outside edge to aid in low light shooting.
Ballistic Plex Design Considerations -
Step one in the development of the Ballistic Plex reticle was in contacting the major ammunition manufacturers to determine the most popular factory car- tridges. To no surprise, .243 Win 100 grain, .270 Win 130 & 150 grain, and 30- 06 150 and 165 grain were clearly the most popular and overall accounted for 70% -80% of the big game ammunition sales. Burris researched the trajectory curves of these loads from several manufacturers and found that the curves were very similar between loads. The Sierra InfinityTM Ballistics software pro- gram was utilized for all calculations and verified by field shooting. An average trajectory curve made lots of sense, and from this, the Ballistic Plex reticle was designed.
As nearly 100% of big game shots are taken inside of 500 yards, providing compensation beyond 500 yards was deemed unnecessay and contradictory to the mission of simplicity. Therefore, the center of the reticle is used as a 100 yard zero, with 200, 300, and 400 yard ballistic lines, and the use of the inter- section of the thin and thick section of the Plex crosshair as a 500 yard zero.
Some would contend (and Burris would agree) that even these cartridges are so flat shooting out to 200 yards, that a separate 200 yard reference is unnecessary. However, significant consid- eration was given to making the use of the reticle intuitive and not subject to the failings of memory for occasional shooters. As designed, counting the ballistic lines is easier starting at 100 yards as the center reference, rather than “remembering” to start counting at 200 and discounting 100 yards. For those who subscribe to the 200 yard zero, a bit of work with the Sierra Infinity Ballistics software program (or other similar ballistics programs) will still allow the shooter to calibrate and optimize the reticle to his particular cartridge, environmental parameters, and shooting style.
Burris Ballistic Plex scopes are of the American-standard non-magnifying reticle design. As you change the magnification, the reticle remains constant in size as the image changes in size. Therefore, the reticle’s size in relation to the image size (reticle subtension) changes, so the amount of trajectory compensation changes as the magnification changes. This necessitates that the scope be set at a specific magnification to be correctly calibrated for trajectory compensa- tion. By design, and with simplicity in mind, the original 3X-9X Fullfield II scopes are calibrated at 9X -- the highest magnification for the scope. On subsequent scopes with higher magnification, Burris may elect to calibrate a higher magnifi- cation scope at an intermediate magnification by installing a calibration dot on the power ring.
The term “Corr@100” is often used in this article and refers to Correction at 100 yards. This refers to how high a bullet must be at 100 yards in order to impact on target at a target further down range. Some would refer to this as synonymous with Minute of Angle (MOA), which is very similar, however would be misused slightly in this discussion. For your reference, one minute of angle is 1.047 inches at 100 yards. 1.000 inches @ 100 yards versus 1.047 inches at 100 yards is small, yet it translates into 1.5 to 3 inches of point of impact variation at 500 yards for most big game cartridges.
There are basically five ways to fine tune the calibration of the reticle to a specific trajectory curve. Any method can be used based on your preferences, however one method may produce the most accurate results compared to the other methods.
1. Sight in at 100 yards. Using a ballistics software program, run a ballistics chart for your cartridge using 5 or 10 yard increments. If the software package does not calculate the Correction at 100 Yards (Corr@100) for each yardage, you can perform this task easily with a spreadsheet. Simply type in the yardages and the Bullet Path like in Example 1. The third column is calculated as follows: Corr@100 for Cartridge = “Bullet Path” divided by “yards” times “100”. Simply match up the Corr@100 for the Ballistic Plex with the Corr@100 for the Cartridge. For instance, instead of the 400 yard ballistic line being dead-on at 400 yards, a less flat shooting cartridge may be dead on at 375 yards, an so forth. See Examples 1 & 2.
2. Sight in at 400 or 500 yards using the 400 or 500 yard ballis- tic line. This will decrease the long range error throughout your self-prescribed yardage limit. This method has the same effect as sighting slightly high or low at 100 yards as is discussed in section 3 below. See Example 3.
3. Another alternative is to do some experimentation with ballis- tics software programs trying several different sight-in yardages from 75 to 190 yards checking each time how closely your 400 or 500 yard trajectory table matches the amount of drop built into the reticle. It can turn out that flat- ter shooting cartridges may need to be sighted in 1/2 to 1” low at 100 yards to best match the rest of the yardages on the reticle, or 1/2” to 1” high at 100 yards for cartridges with more drop than that calibrated into the reticle. Example 2 shows that a 100 yard zero results in nearly perfect calibra- tion out to 300 yards, however 400 and 500 yard calibrations are significantly off. Fine tuning in Example 3 shows that by simply sighting in .9 inches high at 100 yards (the same as a 158 yard zero), allows the calibration to match the reticle to very acceptable hunting accuracy out to 400 yards and is just a bit low at 500 yards which can easily be compensated for by sight holdover.
4. If your cartridge has much more drop than the example car- tridges, you can re-calibrate the reticle to a lower magnifica- tion. Based on actual shooting or trajectory charts, calculate the Corr@100 yards necessary for 500 yards, for instance. The Ballistic Plex is factory calibrated for 55.3 inches of drop at 500 yards from a 100 yard zero. Therefore 55.3 inches divided by 5 is 11.06” Corr@100 in order to hit the target at 500 yards. Therefore, you would need to hold over 11.06” inches at 100 yards to be dead-on at 500 yards. Lets say that with a 100 yard zero, your specific cartridge drops 64.3
5. If your cartridge has much less drop (is flatter shooting) than the example cartridges, you may want to use the center of the reticle as both a 100 and 200 yard aiming reference. This would make the first ballistic line roughly a 300 yard reference, the second line a 400 yard reference, and so on. A good rule of thumb would be to sight in with the second ballistic line at 400 yards which would usually be between a 125 to 175 yard zero with the center of the reticle. See Example 6. Also notice that the Reticle Drop figures start at 300 and go to 600, and differ from the other charts which use the first ballistic line as a 200 yard reference.
Charts and Ballistics Programs Are Close. Actual Shooting is Better.
The nature of ballistics is such that everything is theoretical and if any one of the variables change, so does the ballistic table. At long ranges, changes in environmental factors can add up to significant variances. Temperature affects both muzzle velocity and air density. Changes in humidity, barometric pressure, and altitude can all add up to several inches of trajectory variance at longer ranges. The height that the scope is mounted above the bore should be factored into generating theoretical trajectory charts. Finally, if at all possible, one should shoot at each 100 yard increment at the altitude and environmental con- ditions he is likely to experience while hunting or compet- ing in order to both develop a trajectory chart and to verify impact for each ballistic line of the Ballistic Plex reticle.
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