Projectile launching device

In combination, a projectile and a launching tube therefor, the projectile having a tubular tail portion housing a first explosive charge and a primer for detonating said first explosive charge, a piston axially movable in said tubular tail portion over a limited length under the effect of said first charge when fired, said launching tube slidably receiving said projectile, an axially extending central guiding rod upstanding from the bottom of said launching tube and receivable in said tubular tail portion of said projectile, said guiding rod being slightly longer than the free inner space of said tail portion and having a firing pin at its end to strike said primer, said tail portion having lateral vents therethrough at a height between the ends of the path of movement of said piston in said tubular tail portion, a second charge carried by said projectile surrounding said tail portion and ignitible by said first charge through said vents, and a sleeve rotatable on said tubular tail portion and having holes therethrough registrable with said vents selectively to open or close said vents by simple rotation of said sleeve.