Introduction
Accounting for horizontal Coriolis force with D.O.P.E. is the most simplistic method available and by far the fastest to make use of in operation. Gathering the information required is indeed a more time consuming investment than preparing calculations or extrapolations, however, those inclined towards this hands-on method are at an advantage as the details gathered account for both horizontal Coriolis deflection and spin drift simultaneously - eliminating the need to consider both individually when assembling a ballistic solution.
Data collection
To assemble D.O.P.E. for horizontal Coriolis deflection (and spin drift), targets must be placed at known distances. A vertical adjustment should be applied to allow shots impact the center of the targets, but no horizontal adjustment should be used initially. With no horizontal adjustment applied, the bullet will stray increasingly to the left or right of the target center with distance, even with a well placed shot. This horizontal deflection is the end product of horizontal Coriolis and spin drift working together, and by how far our bullets stray for the target distance is the information we will use in operation.
Target Range Vertical Deflection *Horizontal Deflection* 400m -2.6 0.1 R 450m -3.1 0.1 R 500m -3.7 0.1 R 550m -4.4 0.1 R 600m -4.9 0.1 R 650m -5.5 0.1 R 700m -6.5 0.2 R 750m -7.3 0.2 R 800m -8.0 0.2 R 850m -8.9 0.3 R 900m -9.8 0.3 R 950m -10.8 0.4 R 1000m -11.7 0.5 R D.O.P.E. assembled by a sniper team using an M24 SWS
When collecting D.O.P.E. of any kind, it is critical that collection atmospherics match the operation atmospherics. In the case of measuring accurate horizontal deflection, we will need a range environment with:
- Latitude matching the operation map used
- Altitude matching the operation map used
- Weather matching operation conditions
- Wind turned off
- The same bullets, rifle and scope that will be used in operation
These conditions can be easily achieved by firing and collecting data on the map in use by the operation, by matching the date and time in the editor to the values set on the mission file, and ensuring wind is turned off. To obtain the date and time in use by the mission file, communication with the senior game master is required.
D.O.P.E. example
Sgt McShooty is deployed as a Spotter (Manual) on a Honeybadger. He ranges a priority target at 900m and has prepared D.O.P.E. for his engagements:
Target Range Vertical Deflection Horizontal Deflection 900m -9.8 0.3 R
He recorded that his bullet hit 0.3 mils to the right at 900m, so he gives the sniper a horizontal adjustment of 0.3 to the left, accounting for the effects of both horizontal Coriolis and spin drift.
D.O.P.E. limitations
As with all instances of D.O.P.E., the data assembled is only accurate for the atmospherics in which it was recorded. When these factors change, such as with changes in temperature, altitude or humidity; our recorded information becomes increasingly inaccurate. With small atmospheric changes, such as with normal temperature fluctuations that are seen over the course of a 2 hour operation - adjustments to recorded data can be estimated with success. When larger changes occur, such as with an entirely different set of atmospherics on a separate operation entirely, adjustments to recorded data can no longer be reasonably inferred, and new D.O.P.E. must be assembled.
