Weapons in GTA IV

Weapons are a precious commodity in any GTA game.

Fist

 * With your fist, you have the choice of disarming, counteracting a move, ground punches and kicks, lefts and rights, and uppercuts and jabs. String moves together to create a combo. On some occasions you can preform "Stun" hits. Also, fighting unarmed is the best way to fight someone without killing them, something that can be important in several missions. The combos deal out the most damage.

Knife

 * Knives are very efficient alternatives to firearms. Even a well-armored adversary can be taken down with a few slashes.

Bat

 * The bat can be swung left or right. You can also block attacks with it.

Molotov

 * The Molotov can only be thrown overhanded, which helps to ensure that you throw it far enough that you don't burn yourself. One Molotov can torch a person, it takes a boatload to destroy a car.  It works well for drive-bys, too. Most pedestrians/cops will die once set on fire, but armored targets will only suffer mild damage. It works well when fighting N.O.O.S.E enforcers, because when they're flailing about on fire, you can shoot them easily. OR you can just let them burn and drive away, even though shooting is probably your best bet.

Grenades

 * The Grenade is excellent at clearing rooms full of enemies. They can be tossed underhand when crouched behind a barrier, or overhand while standing. You can "cook" (shorten the detonation timer) the grenade by holding the throwing button. You can also drop these out of your car window to fend off pursuers. They cost 1,000$ per grenade.

Firearms
Unlike the 3rd Generation GTA games, weapons can no longer be purchased at an "Ammunation" type store but must be either found or bought from shady back alley stores or a weapons dealer like Little Jacob once you have won over his friendship. On a GTA IV demo, the gun dealer Little Jacob had a 9mm, an SMG, and a Micro SMG in his car for sale for $100 each, which wasn't "breaking the bank" as the demo started the player off with $7500.

The following is from gtanet.com

Handguns
Handguns are the staple to any crime dog's arsenal. Even in the endgame, pistols are very efficient guns. While generally not a good idea to try to kill someone by unloading into their body, you can make short work of them by shooting them in the head, foot or leg. Recommended for weaker enemies.

Glock
Caliber: 9x19mm Capacity: 17

Developed in the 1980s by Austrian engineer, Gaston Glock, the eponymous pistol soon became the world's most popular civilian and law enforcement sidearm. With its polymer frame and simple, internal striker-fired mechanism, the Glock is both lightweight and extremely durable.

Desert Eagle
Caliber: .357 Magnum, .44 Magnum, or .50 AE Capacity: 9, 8, or 7

In 1979, Magnum Research Inc. set out to create the first gas-operated, magnum-caliber pistol. While the end product is generally considered too heavy and too expensive to serve as a practical combat pistol, it hasn't stopped the Desert Eagle from becoming the weapon of choice for Hollywood (and video game) bad guys.

Sub Machine Guns
Submachine guns are the next step up from pistols. They're most effective a medium range. These are preferred over pistols when doing drive-bys or chasing down an escaping car.

Micro Uzi
Caliber: 9x19mm Capacity: 50

The smallest member of the Uzi family was introduced by Israel Military Industries in 1986 as a security weapon to fill the firepower gap between pistols and standard submachine guns. Between its short barrel and extreme rate of fire, things like aiming are but an afterthought. This gun is not as fast or powerful as the MP5, but it holds more bullets per clip.

MP5 N(A3)
Caliber: 9x19mm Capacity: 30

The Heckler & Koch MP5 was originally developed in the 1960s, but has been further refined and revised over the years into a number of different models. Thanks in large part due to the number of options available, reliability, and accuracy, it is the most widely used submachine gun today. The MP5 is more powerful and faster than the Uzi.

SW MP-10
Caliber: 9x19mm Capacity: 30

The Special Weapons MP-10 (also known as the PXP-10) is essentially an MP5 clone with a custom polymer upper. Not much is really known about it, as it's apparently made in very small numbers by a very small and, err, mysterious company. At this point, it's hard to say whether this appears in the game in addition to the MP5 above, or if the MP5 has been replaced since the older screens..

HK416 Carbine
Caliber: 5.56x45mm NATO Capacity: 30

A revision of the M4 series with improvements such as the "new" gas system also is self-regulating and will work reliably with any barrel length. Other improvements include new buffer assembly, improved bolt, and a cold hammer forged barrel, as well as free-floating handguard with integral Picatinny-type rails. Originally developed as a "drop-in" upper receiver assembly for any standard M16/M4 type lower receiver, HK416 is also available as a complete weapon, with HK-made lower receivers. Current (late 2005) models include carbines with 10.5" and 14.5" barrels, and 16.5" barreled carbine and 20" barreled rifle will be added later.

The Carbine is more powerful than the AK-47, but it holds less bullets.

AK-47
Caliber: 7.62x39mm Capacity: 30

Even after sixty years, Mikhail Kalashnikov's legendary AK-47 rifle is still a hard act to follow; both in reliability and popularity. Created with mass production in mind, the simple design and loose clearances resulted in a rifle that's practically indestructible, and that will remain functional with little maintenance or cleaning.

G3SG/1
Caliber: 7.62x51mm NATO Capacity: 20

The G3SG/1 is a version of the H&K G3 rifle optimized for sniper applications.

PSG1
Caliber: 7.62x51mm NATO Capacity: 20

The PSG1 is another H&K G3 sniper variant. It is unknown if both this and the G3SG/1 will be in the game, or whether the above is only in the art. Probably the latter.

Combat Shotgun (SPAS-12)
Gauge: 12 Capacity: 8

This Italian semi-automatic shotgun was designed by the Luigi Franchi company in the late '70s. Originally intended for police and military use, the SPAS-12 features a heat shield under the pump/handguard to protect the user's hands during sustained fire. While this is a definite plus on a combat shotgun, it comes at the price of added weight.

Pump Shotgun (Winchester Defender)
Gauge: 12 Capacity: 5

Based roughly on the classic Remington 870 (which is also featured in some artwork), the Winchester 1300 line is also known as the "Speed Pump" series thanks to the short, fast cycling of the action. This feature has made the shotgun popular for both sporting and security purposes.

RPG-7
Caliber: 40mm Capacity: 1

This classic anti-tank, rocket propelled grenade launcher was first used by the Soviets back in 1961. It has remained popular ever since thanks to its durability and low cost. The RPG this time around in GTA can even skip off the ground and knock things around that are in its way. This weapon costs 15k to purchase and 5k for ammo. Rockets fired at average sized cars will automatically destroy them, but it isn't that easy with larger vehicles like Biff's. It is, by far, one of the deadliest weapons in the game.

Grand Theft Auto IV