This idea was to try to get AROUND some of the limitations of a gravity assist. For instance, a gravity assist around a large body might require a solar powered

This idea was to try to get AROUND some of the limitations of a gravity assist. For instance, a gravity assist around a large body might require a solar powered spacecraft to be in the shadow of the object for quite some time, rendering the solar panels useless and requiring a radio blackout. Assuming that the method of firing off the projectile and catching it can move gimballed from the rest of the craft, you could allow the ship as a whole to resume the same attitude/trajectory, save for the acceleration of the returning projectiles. Another thought is that if the projectile were small and aerodynamic enough, you could dip closer into a body's gravity well than the spacecraft could due to atmospheric drag, grabbing more momentum than the spacecraft itself could. The lower periapsis might yeild more delta-v due to the more pronounced Oberth effect than the spacecraft could provide. That's all assuming you don't go TOO far into the atmosphere with the projectile.