Function calculate_spin_damping_moment 

pub fn calculate_spin_damping_moment(
    spin_rate_rad_s: f64,
    velocity_mps: f64,
    air_density_kg_m3: f64,
    caliber_m: f64,
    length_m: f64,
    decay_params: &SpinDecayParameters,
) -> f64

Calculate the aerodynamic moment opposing spin

Based on:

• Skin friction on the bullet surface
• Pressure drag effects
• Magnus moment damping