pub const ASM_DENSITY_LB_FT3: f64 = 0.075126;Expand description
Standard sea-level air density under the (older) Army Standard Metro atmosphere (lb/ft^3).
Many published Sierra/Hornady/Barnes ballistic coefficients are referenced to THIS
density instead of ICAO_DENSITY_LB_FT3 — quoting the same physical drag at a
~1.8% different reference air density. Not used by this engine’s retardation math
directly (which is calibrated to the ICAO figure via CD_TO_RETARD); it exists so
ASM_TO_ICAO_BC can convert an ASM-referenced BC to the ICAO-referenced value the
engine expects (BallisticInputs::bc_reference_standard, MBA-1365).