That's a clever insight. I nominate revolvers, but I can't think of any reason other actions couldn't be made to work. Current ones might not do so reliably, but they might only require minor adjustments. While the potential for armed-combat in orbit looks imminent, I'm not sure handguns will be the first choice of weapon. Similarly, while the prospect for combat away from orbit seems improbable for some time to come, I can't imagine a Mars expedition would go unarmed. It's not that we'd expect dangerous green men or something, but the more people that go and the longer they're out there, the greater the chance there will be a need for the use of force. Current travel times to Mars on Hohmann Transfer Orbit is about 7 months, but could be as much as 9 months. Then there is the stay and another 9 months or so return trip.I'm not sure, but the next generation of small arms will have to cycle reliably in outer space.
There are handguns on the ISS.