Are projectiles, not physical objects? Because taking off the collision insta-kill thing of the anti-nuke, now means that they can't actually hit nuke missiles. Also, the game actually let me assign a max hp to a nuke missile.....just thought you would like to know.
Are you talking about "collision_response":"destroy"? IIRC that annihilates both projectiles, and the hp/damage are irrelevant. This was last time I checked. I have seen that missile mod which I am guessing inspired you, but I assumed it didn't work. I hope I can be proved wrong.