This is for  Ultraviolet who wanted some tips on designing sci-fi guns. Anyone else can pretty much use this as well. Please note, these are rough drawings so some of the straight lines are quite wonky. Sorry.

Anyways, above are six guns. Guns two to six are copies of the first gun, a basic looking everyday semi-automatic pistol. A good way to design sci-fi weaponry is take the basic shape of a real life weapon and modify it in several ways. You also need to think about the style of the weapon and what the makers of the weapon had in mind - is it a cheap yet effective weapon? Then it would likely be more close to geometry shapes - all square corners, straight lines and no surplus parts. A more elegant weapon for public show - a sidearm for a guard of honor - would look clean, with sweeping curves and elegant grips.

Gun two - Indents - putting holes and indentations into the original design breaks up the plain parts of the weapon and transforms it into some more...sexier. This is a gun for the heroes, the tough, and the bad guys.

Gun three - Swapped Parts - I swapped the straight barrel with the barrel from a revolver and added some cylinder bits. It's not a big change, but it is different from the usual pistols.

Gun four - Prototype - I chucked in an assortment of random bits and wiring to the basic design. It makes it look like it's a work in progress weapon design and the finished product would be more economical and different from the prototype.

Gun five - Add-ons - I just added a load of stuff to the basic pistol design - a stock, telescopic sights, longer barrel, pistol grip, laser sight, bigger clip, silencer - not very sci-fi but it's a good way to come up with new designs.

Gun six - Glowing - What is sci-fi without glowing lights? I simply added a cylinder to the barrel, cut some holes and added some glowing lights. A simple solution that makes it look very different from the basic design without actually being very different.