
89Analytic and Computational Ballistics
Determining the breech pressure and travel when the solid grains have been completely
consumed is also of considerable interest. We shall use the subscript “c” to represent
charge burnout. If the charge is designed properly, it will burnout somewhere in the bore
that allows us to extract most energy from the propellant and reduces the muzzle blast.
Recall from our previous discussions that at t = 0, x = 0, f = 1, and ϕ = 0 but at all burnt
(subscript“c”), t = t
c
, x = x
c
, f = 0, and ϕ = 1. If we substitute f = 0 in Equations 3.109 and 3.110,
we obtain the breech pressure at the instant of charge bur