BC001 — QUICK USER GUIDE

1. PURPOSE

BC001 determines the ballistic coefficient (BC) from two measured velocities, V1 and V2, and the distance between the measurement points. It then calculates velocity, energy, POI and CLICK correction over the selected range.

2. TERMINOLOGY

• BC — projectile ballistic coefficient for the selected drag model.
• G1 / G7 — drag models for common projectile shapes; BC must match the model.
• GA/RA4 — a model used, among others, for some airgun pellets.
• GS — spherical projectile drag model.
• V1 — velocity measured closer to the muzzle.
• V2 — velocity measured farther away; it must be lower than V1.
• POI — Point of Impact relative to the line of sight.
• ZERO 1 / ZERO 2 — near and far trajectory intersections with the line of sight.
• CLICK — required turret correction; positive means UP and negative means DOWN.

3. FUNCTIONS

• NAME / DESCRIPTION — ammunition or setup name stored in the report.
• UNITS — metric or imperial system.
• DRAG MODEL — selects the G1, G7, GA or GS table.
• V1, V2 and V1 → V2 DISTANCE — required inputs for calculating BC.
• PROJECTILE MASS — enables energy calculation.
• SIGHT HEIGHT and ZERO — define the line of sight and POI trajectory.
• MAX. RANGE and STEP — set the chart and table range and interval.
• ATMOSPHERE — temperature, humidity and pressure or altitude affect air density.
• TURRET SCALE — single-click value. CORRECTION DISTANCE produces one CLICK result for the distance measured from the V1 point to the target.
• V / E / POI CHARTS — velocity, energy or trajectory view.
• TABLE — distance from V1, velocity, energy, POI and CLICK. The “0 · V1 (D1)” row is the V1 measurement point.
• SAVE — quick TXT report; SAVE AS — selected name and location; LOAD — opens a compatible BC001–BC004 report.

4. EXAMPLE

1. Select metric units and the G1 model.
2. Enter V1 = 920 m/s, V2 = 825.7 m/s and a measurement distance of 100 m.
3. Optionally enter a 4.5 g mass, 4 cm sight height and a 100 m zero.
4. Read the calculated BC and inspect the POI chart and table.
5. Save the report with SAVE AS. It can later be loaded into RETICLES.

5. NOTES

BC is displayed in lb/in² with its kg/m² equivalent. A positive POI is above the line of sight and a negative POI is below it.