Introduction and instructions to the TriStar Targets BDC series of targets.
Introduction (Instructions Below)
Long range marksmanship is a difficult yet rewarding experience that many have participated in since the invention of the gun. However, for many of us, simply finding a long distance range is actually becoming the most difficult aspect of shooting. We often encounter backstops sitting at 100 yards if we are lucky and as little as 25-50 yards if we live amongst more populated areas.
If you are one of the shooters who has access to a 100 yard range and subsequent zero at that distance, consider yourself very fortunate. But with that fortune we are still frustrated with the need to shoot further beyond our 100 yard zero. Even if you do find yourself looking at 100s of yards of distances, you still need to at least have an idea of where your rounds will impact at long distances without wasting round after round.
At this point, we must Think Beyond Zero.
We know that we must shoot above our 100 yard zero, but how much is the defining question. And it was with that question that the TriStar Targets BDC series of targets has come about. We know we need to compensate for bullet drop by aiming above our zero when the target lies beyond zero. Our compensation is, at least initially, derived from ballistics tables that can be found at various sources online. Many are produced by ammunition manufacturers and others are computed via ballistic calculators, also found online.
While we can refer to ballistics tables to estimate bullet drop at a given range, it does come with an amount of uncertainty. We need to be sure that for a given amount of elevation required for a specific range, for instance, that our rifle scope does actually shift the Point of Aim (POA) to our desired Point of Impact (POI). We may also need to factor in environmental changes such as temperature change, humidity, and even changes in elevation.
Many of us are familiar with Ballistic Drop Compensation (BDC) in regards to bullet drop. The concept of BDC, at least for the user, is very easy to understand: at any distance beyond zero, our bullet will drop by a somewhat predictable rate. We must make up for the drop by adding some amount of angle to our rifle. These angles are normally defined as Minutes of Angle (MOA) or Milliradians (MRAD/MIL), sometimes called clicks.*
BDC can often be encounter either via dots placed directly upon the reticle (and below center) at defined intervals or on the elevation turret of the rifle scope. Either of these types are good at what they do but also have some drawbacks. BDC rifle scopes of both variations are not conducive to changes in bullet caliber or even bullet weights. They can be thought of as a “about right here” type of tool that gets you close, but with some margin of error.
A rifle scope that is not calibrated to a specific round of ammunition is much more flexible, but the shooter needs to practice shooting at range in order to compensate for bullet drop. Using our ballistics table, we can see that if we have a zero at 100 yards, our bullet will drop by about 'X' amount of inches beyond that zero at a given range. How much do we adjust our scope to account for this? A very simple math formula will give us the answer.
More than likely, you are using a rifle scope that has its elevation turret marked in either MOA or MIL graduations. MILs will typically be marked in 1/10 increments while the MOA are normally found in ¼ or ½ MOA increments. At 100 yards 1 MOA is equal to 1.047 inches. If we are aiming at a target 300 yards away, and our ballistics table indicates we have a drop of 25 inches, then simply divide 25 by 1.047 which results in an increase in angle of 23.87 MOA. In this instance, round to the nearest MOA making on your turret.
MIL markings on your scope are done in a similar method. Since 1 MIL is equal to right at 3.6 inches at 100 yards, we know that we would need to divide the 25 inches by 3.6. The resulting answer would be 8.33 MILS of added elevation rounded to 8.3 MIL.
With the BDC series of targets, much of the math is taken out and you simply need to look at the right hand side of the target to see how much added elevation is needed in either MIL or MOA. Each BDC target, while fundamentally the same, is set to a specific bullet load. And these loads are where each target differs. At a given caliber, 5.56 for instance, a 55 grain bullet will have different rates of drop than that of 62 grain bullets. This is why the BDC targets are not a one size fits all type of target.
Even more important to understand is that what happens in the vacuum of a calculation rarely proves to be 100% repeatable in real life, and that fact includes the BDC targets. There are innumerable variables that occur on the range that would be impossible to account for on a target, the BDC targets being no exception. Each ballistic calculation takes into account muzzle velocity, barrel length, height of the scope over the axis of the bore, and local environment conditions. Simply put, there is no substitution for actual range time. But with these targets, those who must endure limited range distances will get practice that can result in better long range marksmanship.
In the end, the purpose of the BDC target is twofold: 1) give the shooter the experience in adding and subtracting varying amounts of elevation in simulating long range shooting without a long distance range. 2) Allowing the shooter to adjust long range POA/POI at short distances, thus eliminating wasted rounds to “find paper”.
*I normally dissuade shooters from using the term click as it has a tendency to cause confusion when switching between MIL & MOA and even adjustable iron sights.
Instructions for use