
187Weapon Design Practice
the shock bottle. The barrel shock is created as the higher pressure gases being compressed
by the onrushing projectile attempt to push their way into the high-pressure precursor ow
eld. One important concept to keep in mind is that pressure acts in all directions—it is a
point function. Think of the precursor ow eld as “pushing in” on anything that is trying
to come out of the muzzle. Thus, the precursor ow eld actually constrains the ow exiting
the muzzle. The Mach cone is generated by the fact that the uid jet of the gas ahead of the
projectile suddenly sees that there is no more wall constraining it and i ...