This is a detailed list of all of the weapons that you are able to acquire throughout the game, their locations (near top of each description), and how to use them to the best of their ability.
At the end of each description is where all of the technical aspects of each gun are posted. So for those who are not interested in the details can just skip those parts.
You can find the AK-47 in Rassvet, on the platform at the top of the stairs. You can also find it in Chyornaya Peschera Cave Branch in the area where you drop down into. Hold L1 in first-person view to zoom into an over the shoulder view. Press Triangle while holding R2 and hovering over it to switch it between semi-auto (one bullet at a time) or full-auto (five bullets at a time). The AK-47 is the official assault rifle of the Soviet Army. The first model was completed in 1946, and in 1949 it became the standard assault rifle of the Soviet Military. It uses 7.62 mm x 39 rounds (developed in 1943) and a 30-round box magazine originally designed for a different assault rifle.
This is given to you by EVA as part of the story, so you can't miss it. The C3 can only be used on the liquid fuel tanks late in the game. Sorry, but this means no placing it on soldier's backs like in the previous installments of the series (C4). That is what the TNT is used for. C3 is a type of plastic explosive developed in the West for special operations use following World War II. It is composed of 77% RDX and 23% moldable plastic. C3 is moldable into different shapes like clay, and is less volatile than TNT, so a little heat or shock will not be enough to set it off. C3 is extremely easy to handle and highly effective.
 Chaff Grenade
Chaff Grenades can be found in various parts throughout the game (Northeast section of Chyornyj Prud in the shallow water for example). Although when I played through, they seem to be much more rare than other types of grenades. You can disrupt the function of enemy radios and electronic devices for a short period of time. Keep in mind that you will not be able to use your motion detector or active sonar, either. It is an anti-electronics weapon that works by scattering a bunch of metal foil in the air to interfere with radio signals.
You can pick up Claymore Mines set either by you or the enemy by crawling over them. Use your thermal goggles to look out for traps involving these. The M18A1 Claymore is a new type of anti-personnel directional mine developed in the U.S. after the Korean War. The gently curved casing is packed with a pound and a half of high-grade explosives. The side facing the enemy is lined with 700 steel ball bearings. So when the mines explode, the ball bearings simultaneously burst out of the casing. The mine is triggered by an electric detonator, and the detonator has a special motion detector built in. When it is planted, it reacts to anything that comes in line with the front sensor and automatically explodes. This includes you!
 EZ Gun
You have this gun from the very beginning of the game if you have it set on the Very Easy or Easy modes. When equipped, the EZ Gun increases your Camo Index to 80%, and helps you recover your stamina faster. The EZ Gun is a noise-suppressed tranquilizer gun that Sigint designed especially for FOX. It does not have a suppressor, because the noise-suppressing mechanism is built into the tranquilizer rounds themselves. The inside of the powder contains a tiny piston. It is set up so that when the firing gas pushes the piston, the piston pushes the bullet out of the chamber. The firing gas is sealed within the chamber by the piston, preventing it from escaping outside. This is why there is no sound when it fires. It is also fitted with an experimental laser sight. The EZ Gun looks just like a Liberator, a gun that was supplied to the Resistance in Europe during World War II.
The Fork has the exact same attacks as your survival knife. You can get it when you are locked up in the prisoner's cell after being tortured. If you kill an animal with the Fork, you will automatically eat it and regain stamina. Press Square lightly 3 times to do a combo. Press Square hard to do a powerful stab.
You can find Grenades all over the place in this game. With the Grenade, how hard you press down the Square button determines how far you will throw it. The grenades in the game are called RGD-5's, the standard blast-fragmentation grenade of the Soviet Army. The grenade itself is composed of two steel-plated casings, and each of those casings has an inner fragment liner that causes it to burst into over 300 shards when the grenade explodes. The safety pin is on the opposite side relative to the M26, the safety is released when you actually throw the grenade, and it will explode about three seconds later. This means it cannot explode while holding in your hand, so do not worry about that.
The Handkerchief is located in Graniny Gorki Lab B1 West. When you first enter the area from the stairs, follow the hallway around and enter the room on the left at the end. Go to the back left of the room to spot some lockers. The Handkerchief will be in one of them (I think it is the 2nd from the left), so just open them all until you find it. If you use this with CQC, it will put enemies to sleep instantly. You can also press the Square button to disperse the sleeping gas. If you do it three times in a row in the same spot, you will put yourself to sleep. This weapon is simple. It is just a Handkerchief covered in knockout medicine. When the enemies breathe it in, it knocks them out.
 Knockout Cigars
You can also find these in Graniny Gorki Lab B1 West. Follow the hallway around, and this time, take the first room on your right to find them. Pressing Square will knockout your enemies, but you must be in close-range. This is a cigarette-shaped narcosis gun. It is a test model that is being worked on for KGB spies. It is a gun that releases sleeping gas when blown on (like a cigarette).
The M1911A1 is a completely customized .45 automatic pistol given to you by EVA near the beginning of the game. It comes with its own suppressor which can be turned off and on by holding R2 and hovering over the gun and pressing Circle. The following is all of the customization that took place on this gun: The feeding ramp has been polished to a mirror sheen, meaning no feeding problems. The slide has been replaced with a reinforced version. The frame has been iron-welded and scraped down multiple times for maximum precision. The front strap part of the frame has been checkered to prevent any slipping by digging into the hand. The sight system is a 3-dot type. It has an enlarged front sight, giving it superior target sighting capability. The normal hammer has been replaced with a ring hammer that enhances the cocking control and increases the hammer-down speed. The grip safety has been eliminated completely. The thumb safety and slide stop have been extended to allow for more precise handling. The base of the trigger guard is whittled down, so you can use a high grip. The trigger is a long type for easy finger access. The trigger pull is about 3.5 pounds, which is 1.5 pounds lighter than normal. The magazine well has been widened to make it easier to put in a new magazine. The magazine catch button has been cut down low to make it harder to hit it by mistake. The mainspring housing has been changed to a flat type to increase grip, and has even been fitted with stepping so it does not slip from the recoil when firing. Whoever previously owned it also added cocking serrations to the front part of the slide so it lets you load and eject cartridges faster in an emergency. As you can see from above, there is no other gun like it in existence, and is the finest gun that Naked Snake himself has ever wielded.
The M37 can be found in the Chyornaya Peschera Cave (follow the right path before encountering The Pain) or Svyatogornyj East in a cabin north of the area. It is to the right of the little shack that you can get to by landing on the roof from a ledge. The M37 is a 12-gauge pump-action shotgun so it is not accurate at a distance, but up close it will send the enemy flying. It can even blast enemies behind doors. It can take a while to reload though (so do the reload trick by clicking R2 twice). What really distinguishes the M37 is that it is lightweight, and weighs about two pounds lighter than other shotguns. It is so light, that it has been nicknamed the "Featherlight". The one in the game has had its barrel and stock sawed off. It is a modification to make it easier to wield in the jungle environment. Another distinguishing feature is the lack of an ejection port on the side of the receiver. It is ambidextrous, meaning that you can use it left-handed or right-handed with equal ease. It also has a low number of apertures, which means that it will not get jammed up as much with mud or dirt when you use it out in the field.
The M63 can be found in Svyatogornyj East in a cabin north of the area. It is to the right of the little shack that you can get to by landing on the roof from a ledge. It is in the very back room through the door. Hop the crate in the back of the room to get to it. There is also a trap door here, which leads you under the building. It is perfect if you are in Alert mode. It can also be found in Groznyj Grad Northwest. As soon as you enter the area, run to your right past the two sets of tanks, then run straight ahead. When you get to the end, go to your left all the way to the fence. Behind the two barricades is a small storage building. Enter it to find the gun. The M63 is a 501 round machine gun, you can fire a ton of bullets before having to change the belt. It is an American-made system weapon that was developed in 1963. It was originally first developed in Southeast Asia. It is referred to as a system weapon because most of the parts are interchangeable, allowing you to create a lot of different variations from a single original model. It is like a convertible rifle basically. Most of the parts are made by presswork and lost-wax casting. So they can be manufactured in countries that lack a developed technological base. The variation in the game is the belt-fed light machine gun. It was originally designed for use in squad support missions. The M63 is a lot lighter than the M60. If you continuously fire it, Snake will start screaming, this adds some cool dramatic effect when you are shooting tons of enemies down.
The Mk22 is the tranquilizer gun that you begin the game with. (Replaced on Easy and Very Easy modes by the EZ Gun). It comes with a suppressor, and like any other one, it can be worn down. So if you are fighting a boss or if no one is around when you fire it, make sure you remove it. Hold R2 and hover over the Mk22, and press Circle to select it on or off. The Mk22 is the perfect weapon to keep fresh food. You have three cages that you can hold living animals in, so when you capture one with the Mk22, the animal will be placed in one of the cages. Animals that are placed in the cages will not rot like the other foods, and they will taste better ans replenish more stamina. You can also use some animals better as weapons too. For example, you could throw a live snake at an enemy if you wish. You can also go into CQC mode with it along with using your survival knife. It is the perfect weapon to interrogate enemies with. You can also earn a lot of extras if you just use your Mk22. Your rating at the end of the game will be higher, and you can earn new weapons and camouflage uniforms by defeating certain bosses with it. Go into the Easter Egg section to find out exactly what you can earn. The Mk22 you have is just a prototype of the one the Navy is currently developing. It is a heavily modified Special Ops version of the M39 pistol used by the SEALs as a sidearm. The Mk22 comes with a longer barrel so a suppressor can be attached. It uses a slide-lock mechanism, meaning you have to reload a bullet into the chamber every time you fire. The Mk22 is fitted with tall adjustable sights, so the front and rear sights can be used to line up your shot even with a suppressor attached. The magazine safety has been completely eliminated, along with the sheer release lever off meaning the hammer won't fall even with the safety on.
 Mosin Nagant
You earn the Mosin Nagant by defeating The End non-lethally, so use the Mk22 to bring down his stamina instead of his health. Then, after defeating The End, you have to find the sniper rifle yourself. It is located in Sokrovenoo North, in the northwest part of the area I believe. The Mosin Nagant, for many years, was the standard Russian sniper rifle, that is, until it was replaced by the SVD in 1963. It uses 7.62 mm x 54-rimmed cartridges, as does the SVD. The difference is, is that the Mosin Nagant you obtain only fires tranquilizer darts, therefore it is a prime weapon to use if you wish not to kill any enemies.
The Patriot is an assault pistol developed specifically for The Boss; you can earn this weapon for completing the game once. You are then able to use the Patriot any time you wish during your next game. (Start a new game from the completed save file). The best attribute about the Patriot is it having infinite ammo. You can also zoom in with it using L1 in first-person view. You can easily run through the game in less than 10 hours by blasting everything in sight. Especially bosses. If you call Sigint when you have it equipped, it leads to a funny conversation about where it came from and how it uses infinite ammo. The Patriot is modified from the XM16E1. The noticeable changes in the modifications include a shorter barrel and the non-existent stock. The Patriot uses 5.56 x 45 ammunition that is placed into the 100-round drum magazine. The internal feed mechanism is shaped like an infinity symbol.
You can find the RPG-7 at the Krasnogorje Mountainside. It is in a small munitions shack, near the cabin that you enter to meet up with EVA (the one that leads to the mountain over looking Groznyj Grad). The RPG-7 can only be used while standing up or on one knee; this is because the rocket fires as soon as the grenade first starts its descent. You automatically go into first-person view when you equip with RPG-7, and for more precise aiming, hold L1 to use the scope. The RPG-7 is a state of the art portable anti-tank weapon developed as the successor to the RPG-2. It first saw active deployment in 1962 (2 years ago). The launcher and grenade weigh over 20 pounds combined, meaning you have to be still to use it. When fired, the propellant will shoot the grenade out of the launcher. Immediately after that, stabilizer fins will deploy from the back of the grenade. After it travels about 35 feet, the rocket fuel inside the grenade will ignite, accelerating the grenade towards its target. Even if it doesn't hit the target, the safety mechanism will kick in and cause it to self-destruct when it exceeds the target range or after a few seconds of flight. The warhead is made out of the plastic explosive heat. It is capable of penetrating up to 13 inches of armor.
You can find the Scorpion in Groznyj Grad Weapons Lab East Wing. You have to be disguised as Major Raikov to enter this room. When you are ready, go directly right from where you first entered the area, and the follow the hallway around and go north. The Scorpion will be in a room on the left side in this hallway. Another way of getting it is dragging a fallen body of a scientist or enemy to the door, and it will open. The Scorpion has laser sighting for easier aiming in first-person view (hold R1). You can also switch it's firing rate between semi- and full-auto. Do this by hovering over it in the R2 menu and pressing Triangle. The Scorpion is a new type of small sub-machine gun made in Czechoslovakia. It started development in 1961. The model you are using is the Vz-61, which uses .32ACP rounds. It is different from a lot of other sub-machine guns in that it operates on a closed bolt system, so you get a high degree of precision. Another special feature on the Scorpion is the rate reducer, which is a mechanism that also functions as a shock absorber. It locks the bolt in place for a split second when it is in the rearward position. Doing this keeps the firing rate down to a reasonable level, and it also helps make the gun easier to control when firing in full-auto mode. The Scorpion's firing rate is 750 rounds per minute.
 Single Action Army
You receive the Single Action Army after completing MGS3 once if you follow these instructions. SPOILER After killing The Boss and escaping with EVA, Ocelot will appear on a hovercraft and jump onboard to fight you. After the cut-scene, Ocelot will lay two guns down for you guys to duel. Choose the gun on the right, and make sure you fire it directly at Ocelot. Afterwards, a cut-scene will follow with Ocelot giving the gun to you, which you can use on your next playthrough. END SPOILER The SAA is a gun that is just fun to use, but probably should not be used on bosses. One reason it should not be used is it's reloading time, which can take quite a while, unless you use the reloading trick that is. In first-person view, if you move the Right Analog Stick (R3) is any direction, you can do tricks with the gun. Snake will just twirl it around his fingers. A cool trick to do before shooting someone if you want to look fancy. It also has a zoom feature for more precise aiming. Just hold L1 while in first-person view to use it. The SAA was first manufactured in 1873. People started calling it the "Single Action Army" after the Army adopted it as their official sidearm in 1875. The SAA is also sometimes referred to as the "Peacemaker" because a lot of sheriffs used it to keep law and order in the old West. There are many different models of the SAA, but the one Snake has is the "Black Powder" model. The SAA uses .45 Long Colt rounds, and is powerful enough to fire a 255-grain bullet at an initial velocity of 800 feet per second. The muzzle energy is almost 10% higher than the .45ACP bullets the M1911A1 uses.
 Smoke Grenade
You can find Smoke Grenades in various places throughout the game. How hard you hold down the Square button determines how far you will throw the grenade. If you stand still for too long in the smoke, you will start coughing, alerting enemies in the process. When the Smoke Grenade explodes, it creates a smoke screen, hindering enemies and your sight. The combustion agent is a mixture of zinc oxide, ammonium chloride, aluminum, and some other chemicals. When it explodes, it releases a thick cloud of grayish-white smoke that resists dispersion. The grenade confuses the enemy by blocking their field of vision.
 Stun Grenade
You can find Stun Grenades in various places throughout the game. How hard you hold the Square button down determines how far you will throw the grenade. As you can tell by its name the Stun Grenade does not harm your enemies, it only stuns them. The effect will make you deaf and partially blind for a few seconds if you are near. The Stun Grenade is a new kind of weapon developed exclusively at Groznyj Grad. The flash of light that occurs when the grenade explodes is produced by magnesium, which is the same material used in camera flashes.
 Survival Knife
Press Square lightly 3 times to do a combo. Press Square hard to do a strong stab. You start out with the knife at the beginning of the game, and it is the perfect weapon for CQC whether you use it by its self or with a handgun. Metal Gear Solid 3 is the first installment in the series to include a knife.
 SVD (Sniper Rifle)
You can find the SVD in Ponizovje West (which is located on the left side, near the end of the path on Ponizovje South, after the trees), north in a small building near the top of the screen. You can also find it in Sokrovenno South, in a small cabin. You can use the scope by holding L1 in first-person view. Press Triangle either in or out of first-person view, to have the scope zoom in or zoom out when used in first-person view. Your aim is much steadier if lying down. The SVD is the Soviet's top semi-automatic sniper rifle, adopted in 1963. SVD stands for the Russian words that mean "Dragunov semi-automatic sniper rifle". For a long time before, the standard Russian sniper rifle was the Mosin Nagant (what The End uses, and what you can earn. Go to the Mosin Nagant section above to find out more on how to obtain it). The SVD uses the same ammo as Mosin Nagant, 7.62 mm x 54-rimmed cartridges, but they developed a new type of ammo with a tighter firing pattern to go along with it. The rounds for the SVD have a steel core and are 2.5 times more precise than regular rifle bullets.
You can find TNT in various places throughout the game, usually in small wooden cabins. You set the TNT by pressing Square, and when you still have it equipped, press the Circle button to detonate it. You can use radar to see where you planted it, but the signal gets pretty weak. It will only explode in the area you placed it in, so if you leave the area and press the detonator, it will not work. TNT is short for trinitrotoluene, a pale yellow crystalline compound made from a tri-nitrified mix or nitric acid and sulfuric acid. It is used throughout the world as a military explosive. TNT has a low sensitivity and is chemically stable, making it easy to handle. It also has a low melting point, and can easily be shaped by boiling or steaming it. But because the sensitivity is so low, you need a booster to actually get it to explode, which is where the detonator comes in.
 White Phosphorus Grenade (WP G)
You can find these grenades in various places throughout the game. How hard you hold the Square button down determines how far you will throw the grenade. "WP G" stands for White Phosphorus Grenade. What makes these special is that instead of just blowing enemies up, they will set them on fire. Along with yourself if you get too close. The grenade uses white phosphorus to create an incendiary effect. There were originally used by the U.S. military during World War II. Back then, they were known as "Willy Petes" after the first two letters of "White Phosphorus". White Phosphorus is a white, waxy substance that spontaneously combusts when it reacts with oxygen. The combustion temperature is over 5,000 degrees Fahrenheit.
On the Virtuous Mission, the XM16E1 can be found in Dolinovodno under the bridge. After crossing the bridge, follow the curve around and come back towards the screen. Hug the cliff edge until you reach the crevice. On Operation Snake Eater, it can either be found in a supply room in Graniny Gorky Lab Exterior, or it can be found in Groznyj Grad Northwest. As soon as you enter Groznyj Grad Northwest, run to your right past the two sets of tanks, then run straight ahead. When you get to the end, go to your left all the way to the fence. Behind the two barricades is a small storage building. Enter it to find the gun. If you have a suppressor, you can press Circle while hovering over the gun in R2 mode to use it. While holding R2 and hovering over the gun, press Triangle to switch firing mode between one bullet (semi-auto), 3-round burst, or 5 rounds. (full-auto). Hold L1 while in first-person view to zoom in. The XM16E1 is a new rifle out of the West. It is a top-of-the-line rifle that the Army adopted recently on a trial basis. The U.S. military was working on a new concept for a light infantry weapon from the late 40's through the mid 50's. They finally decided on a .22-caliber, high muzzle velocity rifle with full-auto capability. What they came up with was the AR-15, or the "black rifle". The XM16E1 is a modified AR-15 that has been fitted with a bolt forward assist. They are doing performance evaluations down in Southeast Asia, taken from Vietnam. It looks a little different than a normal XM16E1 because it is painted in a camouflage color.