I would assume that in space firing projectile weapons would pose significant navigational challenges. Recoil and all that.
As I am sure you know the US Navy is already developing magnetic rail gun systems. Because the projectile is accelerated using electro-magnetic energy a recoil in the classical sense dose not occur. Rather there will be an energy transfer from the source of the magnetic field within the gun to the projectile and vice verses.
A projectile fired from a spacecraft would continue on its trajectory for millions of miles without loss of momentum. Conceivably that projectile could slingshot around a planet and return to the point of origin destroying the spacecraft that launched it comic book style.