Choose G1 or G7 without breaking the profile

A ballistic coefficient describes a projectile relative to a named reference drag model. FreeDOPE therefore needs the model and coefficient as one paired input.

Start with the source. Find the projectile or ammunition record that supplied the coefficient. Record whether it labels the value G1 or G7. Choose the same model. Select G1 for a G1 value or G7 for a G7 value. Do not choose the model by projectile appearance while keeping a coefficient published for the other model. Enter the matching coefficient. Copy the coefficient with its original precision and keep enough source identity in the profile name or notes to find it again. Verify the resulting curve. Recalculate and compare known distances. A model mismatch often becomes more visible as distance and flight time increase.

Example. If the authoritative source says “G7 0.243,” enter G7 and 0.243 together. Entering G1 and 0.243 creates a different drag description.

Do not guess or casually convert. If the source does not identify the model, stop and find a traceable projectile record or verified profile. A mathematically valid solve can still be based on the wrong drag assumption.

Expected result. The profile preserves a coefficient, drag model, and source that another reviewer can identify and compare with observed data.