Self-Sealing Flechette.
The thin, dart-like high-velocity projectiles with super hardened tips will punch through anything; armor, flesh, equipment and station alike. One won't do a huge amount of damage to a person - much like being hit by a stray miss at a dart-board. It'll produce a yelp of pain, a heated conversation, then a conciliatory round of beer.
5 or 6 of them through a limb will immobilize it, 25 of them will incapacitate the toughest marine. A single lucky shot through the heart or brain will kill.
So, what use is that then if it pierces the station too?
The capsule that fires the dart also fires a small lump of self-expanding foam, that acts like a sealant, tough and flexible. On armor it'll pinpoint where someone was hit, on a station-wall it'll create a seal over the hole, some will get pushed through by the pressure differential, and fix on the hole in the layers below. The vacuum causes it to outgas and "dry", much like any solvent-based glue.
For indirect hits to the station through ricochet or miss, ones that pass through a military target first, such that the sealant gets stopped by the armor - the hole is small enough (perhaps 3mm) that the rate of gas-escape is slow. This gives time for repair-bots to fix the hull at their leisure (when there's no more fighting).
Dart-Doping:
For extra effect, have them release a paralyzing compound on entry, a nerve-toxin that numbs and immobilizes the local flesh, muscle and all - or go the other way, causes severe pain on entry like a bullet-ant sting ("waves of burning, throbbing, all-consuming pain that continues unabated for up to 24 hours").