Metal Gear Solid/Weapons

All weapons are equipped by holding psx: r2 to access the weapons menu, and selecting the desired weapon with. You can quickly equip and un-equip the most recently-used weapon with psx: r1. Weapons are used with psx: s.

SOCOM pistol
The first gun you find in the game. The SOCOM is found in either a cargo truck outside the tank hangar, an open room on floor 1 of the hangar, or in the cell area of floor B1 of the hangar. The SOCOM carries 12 rounds. It comes equipped with a laser aiming module, and a suppressor can be found in the tank hangar inside a level 1 door on floor 1. The SOCOM is the most basic gun in the game; you'll probably find yourself using it far more often than the FA-MAS or the PSG-1, and its usefulness is compounded by the additional suppressor, allowing you to dispatch enemies quickly and silently.

FA-MAS assault rifle
An optional weapon found in the armoury on floor B2 of the tank hangar, inside the level 2 door. The FA-MAS is capable of full autofire by holding down psx: s. It goes through its 25 rounds much faster than the SOCOM can go through 12 because of this, but it can take out even the most heavily-guarded enemy soldiers rapidly. It also packs more power into the last three bullets of each magazine, meaning that you'll need to choose between either burning up a full magazine for the extra power of the last three shots, and taking the risk of the extended reload time, or bottling out and instantly reloading with a double-tap of psx: r1. The FA-MAS is most useful when you're surrounded by enemies, and in sequences such as the elevator ambush in Communications Tower B.

PSG-1 sniper rifle
The PSG-1 is found in the armoury, in the level 5 room. You can only use it in first-person view; you can't move while it's equipped, as is used for aiming. This gun is required if you want to even come close to landing a hit on Sniper Wolf, as no other weapon has the same range. Its usefulness is limited outside of the two battles with Sniper Wolf, though, as you can't move with it equipped, you can only see what its scope allows you to see, it is only capable of carrying 6 rounds, and you can only use it while prone (laying flat on the ground). It does, however, have the distinction of being the only weapon you can use while prone, so it's handy if you find yourself trapped in an air duct because of an enemy patrolling immediately outside its entrance.

Nikita remote-controlled missile launcher
The Nikita launcher is found in the level 3 room in the armoury. It fires a remote-controlled missile that can be guided with after launch. It is required to deactivate the electric floor on floor B2 of the nuclear warhead storage building, and is very useful in the boss fight against Vulcan Raven. Outside of these situations, it, along with the Stinger, is a good choice if you don't want to get too close to an enemy.

Stinger homing missile launcher
Found in the entrance of Communications Tower B. Like the PSG-1, it can only be used in first-person view, so un-equip it with psx: r1 when it isn't needed. Use to aim, and psx: s to fire. The Stinger is capable of lock-on: when the reticle turns red and the weapon emits a continuous beeping sound, it has locked on to a target. Required to take down the Hind D and Metal Gear REX, and also effective in the later stages of the battle with Vulcan Raven.

Grenade
A common find throughout Shadow Moses Island. Press psx: s to pull the pin, and release to throw. Hold psx: s hold for some time before releasing to reduce the time between throwing the grenade and it exploding. Grenades produce a powerful blast capable of killing a large group of enemies at once. The explosion is loud, however, and any enemies still standing afterwards will immediately come to investigate. It is required to defeat the M1 Abrams tank, but is rarely needed after.

Chaff grenade
Another commonly-found weapon. Press psx: s to pull the pin, and release to throw. Unlike the regular grenades, holding a chaff grenade after pulling the pin offers no strategic advantage whatsoever. Unlike the grenade, however, the chaff grenade is one of the most important weapons in the game. Its explosion causes no damage, but its main purpose is much more important - it disables all electronic equipment installed in the room in which it explodes. Since several areas in Shadow Moses Island contain some form of surveillance camera, the chaff grenade will likely prove one of your most used weapons during your mission. Chaff grenades are highly useful against the M1 Abrams tank and Metal Gear REX, both of which use electronic sensors to detect your location when taking aim. Chaff grenades also jam your Soliton radar when used, though in some of the areas most heavily populated by surveillance cameras, the radar is often unavailable anyway.

Stun grenade
Another commonly-found weapon. Press psx: s to pull the pin, and release to throw. Unlike the regular grenades, holding a stun grenade after pulling the pin offers no strategic advantage whatsoever. The stun grenade, upon detonation, stuns all enemies in the vicinity for a short while. Only really useful at the very beginning of the game, before you find the SOCOM, though still handy if you find yourself surrounded and in need of a quick escape.

C4
Another common weapon. C4 is a powerful plastic explosive that can be remotely detonated at any time. Press psx: s to plant C4, then move out of its blast range and press psx: c to detonate it. It is required to destroy the cemented walls in the armoury that seal off the path to the fight with Revolver Ocelot. After, it is useful for defeating enemies at range, particularly those with a fixed patrol path, or bosses such as Vulcan Raven, who is best fought at a distance.

Claymore
Claymore mines are hidden explosives that can only be seen with the help of a mine detector or thermal goggles. They explode when you cross the laser wires surrounding them. You can pick up claymores by crawling over them. Set them with psx: s. Once set, they will become invisible again. Claymores are buried in the cavern where you fight the M1 Abrams tank, the entrance to the underground passage where you first fight Sniper Wolf (only while Meryl is with you), and at the exchange point of the two cargo elevators in Metal Gear REX's underground base. Like the C4, they are useful against enemies with fixed paths and Vulcan Raven, with the added bonus of not requiring manual detonation, and the negative of being completely hidden to the naked eye - including yours.