We put
(5) w/nd2 = C,
and call C the ballistic coefficient (driving power) of the shot, so that
(6) Δt = CΔT, where
(7) ΔT = Δv/gp,
and ΔT is the time in seconds for the velocity to drop Δv of the standard shot for which C=1, and for which the ballistic table is calculated.
Since p is determined experimentally and tabulated as a function of v, the velocity is taken as the argument of the ballistic table; and taking Δv = 10, the average value of p in the interval is used to determine ΔT.
Denoting the value of T at any velocity v by T(v), then
(8) T(v) = sum of all the preceding values of ΔT plus an arbitrary constant, expressed by the notation
(9) T(v) = ∑(Δv)/gp + a constant, or ∫dv/gp + a constant, in which p is supposed known as a function of v.