D.O.P.E. or DOPE, is an acronym and precision rifle shot placement prediction system used by military snipers, competitive precision rifle shooters and high-speed special-ops types that stands for Data On Previous Engagements. To deliver a precision shot at long range, and on-target, DOPE is a broad term used for the capture and practical application of bullet projectile trajectory data for a given rifle and ammo combination during specific weather and terrain conditions. This data is collected in a book, and/or a handheld computer for future reference so that the shooter in a similar situation knows what the projectile will do. The key data elements collected are elevation, windage and correction settings (a.k.a., “Come-Ups”). DOPE can be "soft" DOPE or "hard" DOPE, and during a practical application, most likely, a combination of both. Electronic generated DOPE from a ballistic computer is considered unverified "soft" DOPE. Once it is verified with a real shot under the current conditions, and any necessary correction is applied, then it becomes "hard" DOPE. The two types of DOPE are generally used together, since "hard" shot data is only accurate for a given “point-in-time” weather/terrain condition. However, as “hard” data is collected, it is flowed back into the ballistic computer to further refine the computational model to enhance the accuracy of future trajectory predictions.
If a target is at 1000 yards, and assuming for the sake of example, there are no other factors affecting the placement of the shot (there will be). At that range, the shooter’s rifle/projectile combination may drop 390.5 inches therefore, to deliver the shot on-target, the shooter needs to increase/offset the elevation of the shot by adding 390.5 inches of elevation to counteract the projectile’s drop. Before the shot is taken, the projectile drop in inches is converted to a set of correction values used by the telescopic rifle sight, and “dialed” into the optic’s elevation adjustment. If the telescopic rifle sight uses Minutes-of-Angle (MOA) as its measurement system, the shooter will convert inches to MOA thereby, adding 37.3 MOA of D.O.P.E. to the firing solution. A faster, but less accurate method to adjust for drop is for the shooter, to adjust the point-of-aim by “holding-over” the target using a graduated reference point on the telescopic rifle sight’s reticle. Whichever method is employed, the shooter will always reference Data On Previous Engagements (D.O.P.E.) to determine the appropriate correction value.