In space, normal weapons are so easy to dodge because by the time you see an enemy ship and fire at it, it's already moved out of the way. Now imagine a weapon that travels backwards in time as it flies though space so that when it arrives at its target, it converges with the exact time and location that you saw the target when you fired. So, if an enemy ship is 5 light minutes away. Then your shot travels back in time 5 minutes as it closes the distance eliminating all guess work about where the ship will be.
For purposes of this question, assume this weapon can only travel back in time as fast as light can travel forward in time. So you can target a thing in the past exactly where you see it now, but you cant target something you saw 10 minutes ago.
While such a weapon would seem to work without any major paradoxes when you just have one ship shooting another, what would happen if 2 ships shot at each other with such a weapon. Since both ships could in theory be destroyed before either ship actually fires thier weapons does there need to be some rule that one event will take precedence over the other, or is there a logically consistent way for both ships to destroy each other in this manner since neither ship captain could see any future events that might cause him to change his course of action.