between handheld weapons and ship guns, these are powerful guns that have to be set up before they can be fired, but when set up they are fairly powerful. They would have near the power of ship guns, while being easier to transport, but they still have to be unpacked to be fired. Their primary purpose would be for defense against boarders or as an option for expeditions.
these weapons would have a undeployed mode and a deployed mode. using a screwdriver on the weapon will switch between modes. it takes two hand slots to transport them, and they slow you down.
these weapons would require purchasing with an uplink of some kind, but they could also be expedition loot. they will require ammo.
some basic ideas:
machine guns
multi-shot rocket launchers
anti-tank cannons or punt guns
rapid fire laser cannons