Method and devices for propulsion

A method provides for shooting a missile-rocket. The missile-rocket has two movable parts and a propellant. The propellant is disposed between the one movable part and the first end of the other movable part. The missile-rocket undergoes three phases of acceleration. During the first phase, the method includes the steps of activating the propellant, moving one of the movable parts in response to the activation of the propellant, and urging the one of the movable parts to engage the other one of the movable parts. During the second phase, the method includes the step of urging the other one of the movable parts in response to the engagement. During the third phase, the method includes the step of releasing gases formed by activating the propellant from the missile-rocket to further urge the missile-rocket. The movable parts are preferably a shell and a core. In one embodiment, the core is moved in response to the activation of the propellant and urged to engage the front end of the shell. The shell is urged in response to the core engaging the front end of the shell. Further urging of the core and the shell is by releasing gases formed by activating the propellant from a chamber formed by the core and the shell. In another embodiment, the shell is moved in response to the activation of the propellant and urged to engage the core. The core is urged in response to this engagement. Further urging of the core and the shell is again by releasing gases formed by activating the propellant from a chamber formed by the core and the shell.