BC002 — QUICK USER GUIDE

1. PURPOSE

BC002 calculates velocity V2 at range D2 from measured velocity V1 at D1 and a known ballistic coefficient. It also produces velocity, energy, POI and CLICK charts and tables.

2. TERMINOLOGY

• BC — known ballistic coefficient matching the G1, G7, GA/RA4 or GS model.
• V1 / D1 — measured velocity and its distance from the muzzle.
• V2 / D2 — calculated velocity and its distance from the muzzle; D2 must be greater than D1.
• POI — Point of Impact relative to the line of sight.
• ZERO 1 / ZERO 2 — two possible trajectory intersections with the line of sight.
• CLICK — turret correction; positive means UP and negative means DOWN.

3. FUNCTIONS

• NAME / DESCRIPTION, UNITS and DRAG MODEL — identify the setup and select the measurement system and correct drag table.
• V1, D1, BC and D2 — main V2 inputs. Velocity loss is calculated over D2−D1.
• PROJECTILE MASS — enables V1 and V2 energy calculation.
• SIGHT HEIGHT and ZERO — define the trajectory relative to the line of sight.
• MAX. RANGE and STEP — set the chart and table range and interval.
• ATMOSPHERE — accounts for the effect of air density.
• TURRET SCALE and CORRECTION DISTANCE — define one click and an optional single CLICK result for the distance from V1 to the target.
• V / E / POI CHARTS and TABLE — show the complete prediction. The first “0 · V1 (D1)” row is the calculation starting point.
• SAVE / SAVE AS — save a TXT report; LOAD — opens a BC001–BC004 report.

4. EXAMPLE

1. Select metric units and the G1 model matching the known BC.
2. Enter V1 = 920 m/s, D1 = 5 m, BC = 0.250 and D2 = 105 m.
3. Optionally enter a 4.5 g mass, 4 cm sight height and a 100 m zero.
4. Read V2 at D2, energy, ZERO 1/2, the POI chart and table.
5. Save the report with SAVE or SAVE AS.

5. NOTES

BC must match the selected drag model. A positive POI is above the line of sight and a negative POI is below it.