Unrelated to the alien species known to humans as Slugs.
"Slug-gun" is a general moniker in the Revelation Space universe for a handheld firearm or similar projectile weapon that fired projectiles ("slugs") made of a hard materials, usually metallic, more rarely metallic-ceramic or even more exotic substances. Many slug-guns were simply conventional firearms, while others represented more specialised derivatives.
While investigating in Chasm City, Sky Haussmann bought himself a small, pocket-concealable pistol that fired special "ice-slugs", that were not traceable the same way as metallic or metallic-ceramic ammunition.
While dealing with the threat of the Sun Stealer to the Nostalgia for Infinity along with Ana Khouri, Ilia Volyova armed herself with several weapons, including an older model of needler handgun and an older model of slug-gun pistol, the latter developed in the days of the Europan Demarchy.
Some slug-guns were specialised to fire so-called "ice-slug" ammunition, which melted over time and was thus harder to trace than metallic or metallic-ceramic ammo used in other slug-throwers.
Later, I bought a gun. Unlike the weapon I had stolen from Zebra, and then pawned, it was neither cumbersome nor conspicuous. It was a small pistol which I could comfortably slip into one of the pockets of the greatcoat. It was manufactured offworld. The gun fired ice-slugs: bullets of pure water-ice accelerated to supersonic speed by a captive jacket which was driven down the barrel by a sequenced ripple of magnetic fields. Ice-slugs did as much damage as metal or ceramic bullets, but when they shattered into the body, their fragments melted away invisibly. The main advantage in such a weapon was that it could be charged from any supply of reasonably pure water, although it worked best with the carefully pre-frozen cache of slugs in the weapon's manufacturer-supplied cryo-clip. It was also nearly impossible to trace the owner of such a gun if a crime had been committed, making it an ideal assassination tool. It didn't matter that the slugs had no autonomous target-seeking
capacity, or that they would not penetrate some kinds of armour.
- excerpt from Chasm City 
She slipped the needler into her belt, then slung over one shoulder the heavy ordnance Khouri had obtained from the warchive. It was a dual-gripped hypervelocity sports slug-gun from the twenty-third century; a product of the first Europan Demarchy, clad in curving black neoprene, ruby-eyed Chinese dragons in beaten gold and silver worked into the sides.
- excerpt from Revelation Space 
Slug-guns seemed to use conventional or fairly conventional ammunition clips and magazines:
- Chasm City (2001) - conventional and "ice slug" models
- Galactic North short story anthology (2006)
- Revelation Space (2000) - used mainly by Volyova
|Melee weapons | Whiphound | Crossbow | Clockwork gun |
Slug-gun | Submachine gun | Dart rifle | Electromagnetic needle-gun
"Beamer" pistol | Particle-beam rifle | Plasma rifle | Plasma bazooka
|Ouroborus-class Worm | Weevil-class War Robot | Whiphound|
|SPACECRAFT WEAPONRY AND DEFENCES|
|Magnetic railgun | Boser | Ack-am | Foam-phase Munition | Pin-head munitions |
Camouflaging screens | Hypometric weapon | Bladder-mine
|Cache Weapons | Solar Weapon|