Understanding how your Drop Compensating Reticle works and how to use it are critical to improving your long-range accuracy. After all, the farther you are from your target, the more your bullet will drop before it arrives. If used properly, your DCR can compensate for drop from distances up to and including a mile.
It’s important to understand why Drop Compensating Reticles (DCRs) were developed. In a nutshell, they were created to take the guesswork out of long-range shooting. Soon, custom reticles were developed with dots on the crosswire. Modern reticles come with etched glass dots, hashmarks, and grids make targeting even more precise. These marks are calibrated for specific distances, so the shooter can simply hold the scope to the correct hashmark to compensate for drop. Next, apply the drop information to your reticle system.
The key difference between the many styles of reticles is the position of the focal plane. Each has advantages and disadvantages. The Nightforce 3.5-15×50 F1 scope uses a front focal plane reticle called the NP-R1. This reticle will always subtend one minute of angle for each mark on the vertical crosswire. Subtension is the measurement between the marks. It increases in size as the distance increases, according to MOA.
As long as we have the necessary information, we can build a drop chart that outputs the MOA correction for different ranges. If we go back to the program at www.gseven.com and put in our True BC and velocity, along with sight-in conditions (we’ll use 100 yards), altitude, and temperature, we can output a drop chart in MOA. For this example, we’ll use a 7mm Rem Mag case with a 168 VLD bullet right at 3000 fps muzzle velocity and a True BC of .648 in my gun. My range is at 4200 feet elevation and the temperature is about 50 degrees in the morning.
The second type of reticle is mounted at the rear focal plane. This type offers one distinct advantage over the front-mount type — the apparent size of the reticle stays fixed as magnification is increased or decreased. This means that the subtension changes relative to your target. This allows you to set the marks on your elevation bar to match an exact range.
The setup on one of these scopes is a bit different. We’ll use the popular Burris Ballistic Plex as an example. This displays the drop in inches for 200, 300, 400 and 500 yards. A simple approximation for the MOA subtension is (drop in inches) / 1.047 / (drop distance in yards/100) so 55.3”/1.047/5yds=10.5 MOA for the “500” yard mark on the reticle. The 400 would be 7.2 MOA, the 300-yard mark would be 4.3 MOA and the 200-yard mark is 1.5 MOA. These subtension amounts are typically referenced for the highest magnification setting. The scope will need to be set on 14 for valid MOA subtensions when using a Burris 4.5-14X42.
If we compare our drop chart against the reticle sub-tension and we manipulate the zero, we find a pretty good fit at 14 power with a 275 yard zero, because we need about 10.2 MOA’s between 275 and 700. However, this is a very flat shooting cartridge. A slower cartridge and a lower BC may require setting the scope on a lower power.
The main things to remember are to calibrate your reticle to True Ballistics that have been verified in the field, practice shooting at odd ranges in varied wind conditions, build your confidence, and know your limitations. A one-shot kill is the only acceptable goal.
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