An excellent point. Space travel would have enough problems with space junk that was accidental in nature without adding projectiles flying all over the place.
the projectile could be made to explode after having traveled beyond their target. For that matter, a guidance system could be incorporated into them minimizing misses. Ideally, the projectiles would have to be rocket propelled as opposed to the usual gun powder to avoid the recoil issue. The warheads could then be loaded with a semi automatic guidance mechanism and an appropriate amount of explosive and by explosive I mean anti-matter of course.