This software incorporates a set of tools for the shooter to wring the most out of his equipment and to maximize the chances of a cold-bore, first round hit on target. To use the tools requires a certain level of competence and effort. If the shooter either does not have the level of knowledge necessary to engage this software or does not want to expend the effort necessary to develop the data necessary to create useful and meaningful trajectory output, then he will not be able to get the most out of his software investment.

Preparing to Use this Program: The Three Important Steps

Calibrating the Scope - The only way a shooter knows how much his bullet actually drops over distance is by using the elevation turret of his scope to tell him how much elevation was required for the shot. What if the turret isn’t accurate? What if the click value of the scope isn’t what the manufacturer says it is? What if the click value is off by 4%, 7% or even 10%? For example, a Leupold Mk V, M3 is advertised to have a 1 MOA per click turret. A shooter who is shooting the .308 Win cartridge may find that it takes 42 clicks from a 100 yard zero to be on target at 1000 yards shooting M118LR ammunition and would therefore assume that for the conditions at hand, the bullet drops 42 MOA at 1000 yards and any computer program that forecasts a different theoretical result is simply wrong. After all, one doesn’t argue with reality.

If the shooter were to put on another scope on the same rifle, he would expect to dial in 42 MOA and be right on target. That may or may not be the result, however, because it is not necessarily the case that the turrets on the scopes are moving the reticle the same amount - on scope one, the turret says 42 MOA but in reality it may have moved the reticle only 40.7 MOA; on the second scope the turret says 42 MOA, but it may have moved the reticle 42.9 MOA. Just because the manufacturer says that a given turn of the turret moves the reticle a given amount on the target is NO assurance that it in fact does. The shooter needs to check. This is the essence of scope calibration.

The first thing any long range shooter must do is to calibrate his scope to determine exactly how much the reticle moves with each click of the turret and NOT to take the manufacturers word for it. The desktop program allows the user to print out five sheets of 8½ X 11 paper, each with chart lines printed thereon. Assemble the five sheets in order on a cardboard backing of some sort and place the chart at 100 yards or meters. (If the desktop program is not available, just take a long sheet of paper about 45 inches long, put a visible mark at the top and one at the bottom. Use the top mark as the starting point and move the reticle to the bottom mark.) Fix the rifle in a vise or with sandbags, dial the scope to zero, align the horizontal element of the reticle at the "0" (or top) line on the chart and then dial in 40 or so MOA and watch the reticle move down the chart. Keep track of the number of clicks of the turret and note the line number on the chart. Do this a few times to assure an accurate measurement. Now that the number of clicks has been recorded for a known distance of travel, double check the distance traveled on the chart by measuring the distance on the chart with a tape measure. Then use this data to compute the ACTUAL click value of the users scope. The program has a computation dialog box for this purpose and requires as inputs the actual and accurate range at which the measurements were taken, the number of clicks of the scope, and the corresponding distance the reticle moved on the chart or target. Once the user knows the actual click value of his scope, he can use this value 1) to compute the actual drop of the bullet at range; and, 2) use this value to compute the exact turret setting for any firing solution computed by the software. This value is used in the Turret Profile so the program can accurately calculate a turret setting for any given drop.

In obtaining this data it is important that the shooter accurately measure the actual distance between the scope at its turret and the face of the target. Either use a good rangefinder (one that has an error factor of under a yard) or a tape measure. Errors in distance will have a definite effect on the calculations. You only have to do this once for each scope, so do it carefully.

Computing the DK - Most all ballistic programs will compute a trajectory based upon muzzle velocity, bullet configuration (i.e., the ballistic coefficient), and atmospheric conditions. This program uses the same data. But, this program also calibrates or customizes the trajectory to the cartridge/rifle/shooter. Bullets from different manufacturers differ slightly in shape and even though they may have similar ballistic coefficients, the rate at which they decelerate can be very different. The manner in which a shooter manages his rifle, i.e., the interface between shooter and rifle, differs from shooter to shooter, rifle to rifle. This is one reason why two shooters who shoot the same rifle using the same ammunition can have bullet groups located at two different spots on the target. To have truly accurate trajectory computations, it is necessary to tailor the trajectory computation to the cartridge/rifle/shooter system and this program allows the user to do that.