Unknown Distance or just UnEven Distance
In the precision rifle world we use two major types of targets out there, The Known Distance target, or KD, and the Unknown Distance Target or UKD. We also have things like movers but that’s another story. For now we’ll focus on UKD vs KD.
A Known Distance targets is what we find at our local or NRA type ranges. The distance is given to you ahead of time, big bold signs that tell you how far away from the target you are. 300, 500, 600, 800, etc, these ranges are usually every 100 yards in distance and used in KD competitions like F Class, Benchrest, even Metallic Silhouette shooting, which is usually measured in meters vs yards. It is at these Known Distance ranges where most people DOPE their rifles. You shoot and verify your drop at these marked distances and record the information in your data book.
A typical range card might look like:
Unknown Distance targets are all those targets in-between, where the range is not given to you up front. The shooter is required to verify that range to target and in most cases figure out the DOPE based on the recorded drop closes to the Known Distance range previously shot. If we used 4.4 Mils for 600 yards and 5.7 Mils for 700 yards, a target that was 672 yards away would fall roughly 80% towards the 700 yard number. This imprecise method along with errors in ranging used to make the UKD target very difficult to hit. The ranging error was usually where the biggest mistake was made. It was common to think Unknown Distance targets had to be ranged using the scope’s reticle.
Reticle ranging is a legacy skill, that means it’s no longer the default method to identify the range of an Unknown Distance target. Today we use default to laser rangefinders, which are faster, more precise, and have a smaller error factor. Highly skilled reticle ranging takes time, practice, and still might come with a 5% error factor even if you do everything correctly. The math just doesn’t lend itself to +/- 1 yard or better. In the military we addressed this with a map study and reference points. Reticle ranging was really just “Flash Milling”, assuming everybody was 36” from head to crotch, and you flashed your reticle up to compare it to the map location from the Final Firing Position. You really don’t want to do long hand math in the field. Wrong time to break out the calculator, instead consider charts made up ahead of time. No doing long hand math also applies to wind formulas, again, another topic.
At the end the day, unless you verified the range, all targets are Unknown Distances. Errors are made all the time, even KD Ranges could be off a few yards. Never trust the posted range, verify.
Ballistic computers are everywhere, there is not a shooter with a smartphone who doesn’t have a ballistic solver installed. Heck with the free ones on the market why would you not. Unknown Distance targets are no longer, Unknown, they are just Un-Even. We can put the exact range into the computer and get an exact drop providing you verified the data and/or trued the solver ahead of time. Garbage in, still equals Garbage out. The shooter still has to do their part in all this.
Combined with a laser rangefinder, Known Distance Targets are merely UnEven.
A laser, like your ballistic computer still requires training and understanding of the limitations of the device. And believe me, not all lasers are created equal.
Quality and reliability is improving everyday, but like most things, you get what you pay for. Lasers have a limitation in not only beam divergence, but under varying conditions. Bright sunlight is a big time limiting factor most people don’t think about. A laser that might only reach 600 yards in bright daylight can easily reach out further at night, the only problem is, you can’t see the target. So invest wisely in your laser rangefinder because it matters. Understand where the pluses and minuses of your device.
When possible, support the laser with a tripod or rear bag placed on top of the rifle. Using a free hand hold is the least accurate method of employing a laser.
After that, it’s all just an uneven distance target, and no longer unknown. Accuracy can be every bit as precision as shooting on a KD Range.
Use the computer to dope the exact range and while you’re at it, consider determining your exact zero range. You may think that 100 yard zero is truly a 100 yard zero. The computer might have other ideas about it. Take a look at what Hornady is doing with this subject. It may seem like overkill but it can help.
Success with a precision rifle at long distance is all about shaving errors. We use the tools available to us to shave these errors so it’s really just about us the shooter. Reducing that 5% error to 2% can yield big gains at long distance.
Because knowing is half the battle
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