Ballistic solution example: calculation
Preparation
Sgt McShooty is deployed as a Spotter (Manual) on a Honeybadger. He aims for to be able to assemble a ballistic solution in any conditions, so he prepares calculations for the operation.
His sniper is using the M24 SWS and they will only be using the M118 LR bullet. Prior to operation start, he looks at an ATragMX to record time of flight for his given atmospherics.
| Target Range | Time of Flight |
|---|---|
| 400m | 0.61s |
| 500m | 0.79s |
| 600m | 0.99s |
| 700m | 1.20s |
| 800m | 1.43s |
| 900m | 1.68s |
| 1000m | 1.95s |
Target requirements
In operation, Sgt McShooty identifies an OPFOR machine gunner engaging a friendly squad. A follow up shot will not compromise any objectives, so he can disregard most Tertiary Components entirely.
In addition to this, he is presented with fairly typical shot conditions, as:
- There is no wind present
- The target is stationary
- He is not firing at a steep incline
| Category | Ballistic Component | Direction of Deflection |
|---|---|---|
| Primary | Bullet Drop (composite) | Vertical |
| Primary | Moving Targets | Horizontal |
| Primary | Crosswinds | Horizontal |
| Secondary | Inclined Shooting | Vertical |
| Secondary | Spin Drift | Horizontal |
| Secondary | Coriolis Effect | Horizontal |
| Tertiary | Eotvös Effect | Vertical |
| Tertiary | Headwinds & Tailwinds | Vertical |
| Tertiary | Air Density changes | Vertical |
Ballistic solution assembly
Bullet drop
Sgt McShooty ranges his target at 800m according to Milliradians: Mil-relation formula FM/BG-522.
Looking at his range card, he finds a bullet drop adjustment of 9.1 mils.
Spin drift
He uses the Spin Drift formula to calculate horizontal deflection according to Spin drift: calculation FM/BG-558:
((SG * Time of Flight ^ 1.83) / Distance) * 1000 = Spin Drift in MRADs
((.0759 * 1.43 ^ 1.83) / 800) * 1000 = .18 MRADs
Because his barrel twist is right hand, his bullet will deflect .18 MRADs to the right.
Coriolis effect
He uses the Horizontal Coriolis Effect formula to calculate horizontal deflection according to Horizontal Coriolis force: calculation FM/BG-553:
cos(latitude°) * (Time of flight in seconds) * .072 = Horizontal deflection in MRADs
cos(35°) * (1.43) * .072 = .08 MRADs to the Right
Final ballistic solution
Sgt McShooty adds his two horizontal components together for a total of .26 MRADs to the right.
Because his deflection is low and to the left, he tells his sniper to adjust up and to the right
Final Ballistic Solution: 9.1 mils up, 0.26 mils left
