Arbitrary Maximum Range: Well, hardly arbitrary. Very carefully programmed maximum range, in fact, since missiles are not jolly things to have ploughing on and on into space without a self-destruct mechanism, or more precisely, for acknowledgement-of-the-kinetic-kill-factor, a deceleration-before-exploding and/or deceleration-and-call-someone-for-pickup mechanism. And then there are the fluffships, giant self-propelled balls of kinetic foam and kinetic barriers whose job – one of the acknowledged worst in the fleet – is to police the debris, railgun ricochets, etc., left behind after a battle in order not to FOD someone’s day.
But in the general case, yes, kinetic weaponry has no particular maximum range, or to put it the now-standard way, Sir Isaac Newton is the deadliest son-of-a-bitch in space. (Even when he’s another civilization’s version and named Siao Callaneth.)
Energy weapon range is essentially determined by beam dispersion, and so is long. Very long. A convenient saying for Sir Isaac’s photonic equivalent has, alas, not yet been found.
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