A gun's appearance has very little influence on its operation - but it can drastically alter how it is perceived. Scary black guns do exactly the same job as more traditional ones: They just look better doing it. The SPAS-12. A distinctive-looking shotgun with some interesting features - and a commanding form.

So, who was this special-purpose shotgun designed for? What gives it such an impressive on-screen presence? And why doesn't anybody ever unfold the stock? Franchi are an Italian firearms manufacturer, founded in 1868. Best known for their sporting shotguns, they made an attempt to diversify in the post-war police and military markets.

One such design was the SPAS-12, in 1979. Dubbed the 'Special-purpose Automatic Shotgun', it was intended to be a flexible platform to fit the varied needs of non-civilian use. Its folding stock reduces overall length significantly - permitting storage in a smaller space, and greater flexibility in close quarters.

The weapon also features a unique hook brace which permits one-handed firing - ideal for shooting through car windows while driving, should the need ever arise. A distinctive square heatshield also protects the user during sustained fire - but perhaps the most interesting aspect of the SPAS is its dual-mode operation.

With it, you get the best of both worlds: the firepower of semi-automatic operation with full-powered loads; and the ability to cycle specialist or less-lethal rounds via pump-action. This versatility was its key selling point: but it came at a cost.

Two modes of operation add weight and complexity: the SPAS-12 is a capable combat shotgun: but it is both heavy and expensive. Its success was further stymied by legal restrictions on imported weapons in the US: not even amending the acronym addressed the 'lack of sporting purpose' found in a military-style weapon.

A number of variants were made to better fit legal requirements, but US imports were quashed entirely in the 1994 Assault Weapon ban. Later prototypes introduced detachable magazines, leading to the SPAS-15 design in 1986. While mildly successful in its own right, in terms of popularity it simply doesn't hold a candle to the SPAS-12: it is by far Franchi's best known weapon.

While the shotgun enjoyed some success within military and police roles, the majority of its reputation stems from its depiction in popular culture. Its distinctive appearance sets it apart from ordinary shotguns: a sleek black exterior, perforated heatshield and imposing squared-off profile.

Because of this, the shotgun has found its place in a wide variety of films: The Terminator, Robocop, Jurassic Park - even the M41A pulse rifle from Aliens borrows the SPAS-12's front end. It's black and mean - and a darling of the silver screen. Its success in cinema has translated to video games, and the weapon is a relatively common sight in first person shooters.

The dual-mode operation of the SPAS permits switching between pump-action and semi-automatic as needed - but games almost never seem to implement this. Instead, they'll choose one firing mode and balance the weapon around it: meaning the SPAS can have radically different behavior between titles.

Pump-action portrayals are more powerful, with a slower rate of fire: the pump animation mandating a pause. Devastating performance better mimics the SPAS-12's imposing exterior - but in reality the pump-action mode is reserved for low-powered rounds.

Semi-automatic operation is the norm for standard cartridges, and many games do show the SPAS-12 this way. The ability to rapidly spew 8 rounds in short order is overwhelming, so within the scope of multiplayer games the per-shot power is reigned in compared to any pump-action.

The tube magazine finds itself empty quick, too - with cartridges inserted individually, you can easily spend more time reloading than shooting. Still, whether through volume of fire or single-shot devastation, the SPAS-12 is normally a very powerful close-range option - as would befit a shotgun of this stature.

The ability to use a wide variety of cartridges means it is sometimes depicted as firing specialist rounds - moreso than a traditional shotgun. Incendiary 'dragons breath' rounds crop up every so often: setting the world ablaze with a fury of fiery shells.

Rarer than buckshot, but an uncommon thrill. A complex weapon with some interesting features - which leads to some unusual mistakes. The folding stock with its circular cut-outs is a particularly recognisable feature of the weapon - but in use, it works best when placed against the shoulder.

Unfortunately, in games this would mean the stock would be far less visible - and so it's often left folded on top of the weapon: quite distinctive but ultimately useless. Still, less forgivable is the depiction in Half-Life and its sequel: quite how the SPAS-12's single barrel can fire two shots at once is a mystery.

Designed for duty - but destined for fame. An imposing presence that has garnered great acclaim. Powerful both in form and in function: from classic 80s action cinema to first person shooters today, its depictions span decades - and yet it remains a favourite.