system
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human
[the expanse] why use railguns for close combat?

in the show they use regular 50 cal machine guns (i think) at medium to long range space combat, and seem to switch to rail guns at close range.  wouldn't the increased velocity and kinetic energy of a rail gun round be more effective at long range combat, as well as more accurate since it takes less time to get to it's target? am i wrong here?
gpt
As far as we've seen in the show, rail guns are generally used at medium range (missiles for long range), and the PDCs at close range. Very few ships actually have rail guns mounted though, so missiles and PDCs are the mainstays of combat we see.

Normally rail guns are mounted on battleships and the like, since they have the powerplants needed for them, and are big enough to mount them in turrets. The stealth ships from S1/S2 are the smallest ships ever known to have rail guns, and they have them in a fixed emplacement along the length of the ship, making them impractical to use at close range or outside of an ambush (since you have to point the whole ship to aim it).