1 The velocity of the bullet after firing is about 1000 m/s. ..

The key depends on where to launch. If it is in the solar system, the warhead also carries the vector of the solar system and its own vector.

When encountering a celestial body with enough gravity, it depends on the relative speed of the warhead and the celestial body. If the relative speed with this celestial body is the first cosmic speed (with the cosmic speed on this celestial body), it will be captured and run around this celestial body, or directly collide. If the speed with this celestial body reaches the second cosmic speed, it will break away from its gravity and continue flying until it meets other celestial bodies. There are no gaps in the universe.

That's all I can say. In fact, there are still many problems.