The Glock 18C is a handgun that at first glance looks exactly like Glock's widespread Model 17 9x19mm pistol. The only visible differences are a small dial-like selector on one side, a compensator (gas vents) along the slide, and a slightly protruding barrel. When holstered, even a gun expert could be forgiven for mistaking the G18C as its more popular and civilized older brother, the G17. But the two guns can't be more different; where the G17 is your standard 9mm handgun, the G18C is considered a machine pistol.
The Glock model 18C is an incredibly inaccurate fully automatic pistol. With the ability to select between full automatic fire and semi-automatic, the Glock 18C is a very versatile weapon. The Glock 18C uses a keyhole opening known as a compensator on the front section of the slide that vent gases upward when fired, thus reducing the felt recoil. It also uses the standard 9x19mm ammo used in a variety of semi-automatic handguns. This gun very similar to the Glock 17, the external differences are the rate of fire selector on the rear left of the slide, and to a lesser extent the extended barrel and compensator, as they are both available on various model 17 pistols manufactured by Glock. The model 18 also uses the same 17 round magazine as the Glock 17, and also can be equipped with a 33 round magazine that extends below the magazine well.
Originally designed as a small full-auto weapon for Counter-Terrorist use, it's been used by agencies such as the U.S. DEA (Drug Enforcement Administration) in some situations. Though still technically a handgun, it's actually a fairly good shot using single shots, although the recoil while using full automatic mode renders this firearm a 'spray and pray' weapon. The 18C also uses its 33 round mag fairly quickly, with a 17 round mag gone in under a second.
Rifling is a hexagonal profile with right-hand twist of one turn in 250mm (9.84 in).
Sight radius: 165mm (6.49 in)
Weight(no mag): 620g (21.87 oz)
Weight(with mag): 900g (31.74 oz)
Trigger pull length; 12.5mm (0.5 in)
In Metal Gear Solid 2, the Glock 18C is Fatman's preferred weapon other than his explosives; one of his favorite pastimes appear to be disassembly and maintenance of his Glock. It is also worthy of note that it would be nearly impossible to fire this weapon automatically while on rollerblades, due to the G18C's recoil. It would also be incredibly inefficient because his skating would only serve to lower his accuracy further.
In MGS4, the player has a chance to wield this machine pistol. It is available for purchase from Drebin during Act 3, and can be customized with a Handgun Light. Drebin himself also possessed at least two Glock 18s inside his Stryker, presumably as weapons to be sold. It may be inaccurate even at short range, but it can be deadly in CQC. If Snake closes to spitting distance, the Glock's high rate of fire can down an enemy in less than a second, but the nature of the weapon may leave one with significantly less ammo than what would be preferable. In addition, some members of the South American rebel soldiers were able to use Glock 18Cs, which also acted as an alternate way to get the weapon.
In the novelization for Metal Gear Solid, Master Miller utilized a Glock 9mm stored behind a clipboard with several handguns when his house was broken into, but never got the chance to use it prior to his death by nerve gas poisoning. The exact model is never specified.
In Metal Gear Online, the G18C is available as a secondary weapon for 1250 Drebin Points. While remaining a relatively weak weapon, the Handgun+ skill would not only compliment the high rate of fire with quick reloads, but would all but eliminate the devastating recoil. Using this weapon in combination with Auto-Aim would theoretically eliminate any worry about recoil, as AA locks on to the center of mass: the chest. The Glock is often favored by snipers because of its full-auto capabilities while remaining a secondary weapon.