Uncharted 2: Among Thieves/Weapons

Throughout the game you'll find various weaponry to assist you in defending yourself against bad guys and making your way through the environments. You will be given some weapons and find others, but the majority of your best armament will come from looting the bodies of your fallen enemies. It's a good idea, whenever you've finished clearing out an area, to go around weapon and ammo collecting before moving on. Although you can only carry four grenades, one primary weapon and one handgun, you can take all the ammo you find. When you switch to another weapon you find, you'll have the ammo you've collected so far (up to the weapon's max) as well as whatever is in the gun. Using stealth attacks can increase the amount of ammo that comes along with a weapon, and this can be noted by the blue ninja symbol when you pick it up. It's a good idea to familiarize yourself with all the weapons during the game, because you'll want to use the right tool for the job to make clearing specific scenarios easier.

Primary
Primary doesn't necessarily mean you should use these weapons first or more often, although they are generally more powerful and carry more ammo than the handguns. Primary simply means you need both hands for this weapon, so you can't use it while manipulating something else or climbing. There is a great variety between the different primary weapons, and some are extremely powerful. There is usually a tradeoff between power and ease of use, so you'll want to assess the situation before picking one or the other. Some weapons are better for run-and-gun tactics, while others will be helpful for taking our groups or heavily armored vehicles.

AK-47 Assault Rifle
This is the earliest assault rifle you'll have access to, and as such is indispensable on the ../Borneo/ chapter. Assault rifles are great general purpose primaries, as they can carry a lot of ammo and fire very rapidly. The thing to watch out for is reticle drift, as holding down the fire button tends to kick the barrel up. This weapon has an advantage over non-assault rifle primaries in situations where you're behind cover in a shootout with medium to long range enemies. If you have a choice however, some of the other rifles will give you better power and accuracy.
 * Clip: 30
 * Max ammo: 150

Crossbow
The crossbow starts to be features once you get to Tibet, but isn't very useful until later chapters. The bolt is powerful, but the weapon is slow and takes a while to reload. The crossbow becomes an absolute necessity however, when fighting the Shambhala protectors. These half-man, half-beast enemies are extremely tough, but go down with a single hit from their crossbows, as though it were magic.
 * Clip: 4
 * Max ammo: 12

Dragon Sniper
Like any weapon, there is a time and place for the sniper rifle, and running around shooting at close quarters isn't it. Only use this weapon when you have decent cover and can take enemies out from a distance. Most enemies are extremely precise shooters, so you'll still want to move from cover to cover occasionally to throw them off. The game is usually pretty obvious about where you should be using the Dragon (mainly right where you find them), and afterward you'd do well to pick your original primary up or find another before moving on.
 * Clip: 5
 * Max ammo: 10

FAL Assault Rifle
Of the assault rifles, the FAL is the heaviest in terms of power, and has the added bonus of a light scope. This is a great weapon for starting a firefight from cover before the enemies notice you. Whenever you can, use the weapon's zooming capability to get headshots on enemies peeking up from or around cover. Depending on the chapter, it may not be the best weapon to stick with, as ammo for it scarce in most places.
 * Clip: 30
 * Max ammo: 150

GAU - 19
This heavy chaingun is capable of laying down an extremely heavy base of fire, and rips through enemies with ease. It has some major drawbacks though, such as freestyle aiming and reduced movement speed. When you're carrying the GAU, you move at a snail's pace, and mobility is often your best defense in the game. There's also bit of delay before shooting as the gun winds up, so trying to nail enemies when they peek around cover is problematic. For the most part, there's no good reason to use this weapon except for the thrill of it. If you're having trouble holding your own against the bad guys, drop it and switch to a more suitable weapon.
 * Clip: 500
 * Max ammo: 500

M32 - Hammer
The Hammer is an automatic grenade launcher, capable of taking out multiple enemies with a single hit as well damaging armored vehicles and helicopters. You don't often get ahold of this weapon, so when you do, take advantage of it. You can't do without this weapon in certain situations where you're fighting a large vehicle, and it works great against some of the tougher enemies, like the black armored shotgunners and chaingunners. It has decent range, but the round is very slow, so if you're attempting to hit a moving target, you'll need to lead it. The Hammer doesn't hold much ammo, so use it wherever you find it to get the most out of it, then replace it as soon as possible.
 * Clip: 6
 * Max ammo: 12

M4 Assault Rifle
The M4 is the best assault rifle in the game, with great accuracy, range and ammo capacity. In the later chapters, this is the weapon of choice among the enemy forces, so you'll have an easier time keeping it loaded. Like all assault rifles, this is a great weapon for shootouts when you're behind cover fighting with a force at a medium to long distance.
 * Clip: 32
 * Max ammo: 160

Moss - 12 Shotgun
This is the first shotgun you come across and makes the game even easier on easy difficulties. It's also a lot of fun to run around blasting guys from close range. Due to it's limited range and low ammo capacity, you won't get much use out of shotguns on high difficulty levels, where cover and fire strategies are needed. If you know you're going into a close quarters battle, such as times when you'll be running through buildings, it's a usable option.
 * Clip: 6
 * Max ammo: 12

MP40 Submachine Gun
Here is another assault rifle, not all that distinguishable from the M4 or AK-47. It has good power, and all the great things about assault rifles, such as accuracy, range and ammo capacity, so it's still a valid choice for most situations you'll find yourself in.
 * Clip: 32
 * Max ammo: 150

RPG - 7
The RPG - 7 is a single-use missile launcher that should only be used when you need to take out a vehicle or a chaingunner enemy. It's easy to miss individuals with it, and it takes time to load and fire, so it's best used for its intended purpose, rather than against troops. A more important facet of this weapon's existence in the game, is that the enemy frequently uses it. When that's the case, make sure you take out the RPG gunner first, or the rest of the battle will be hard fought.
 * Clip: 1
 * Max ammo: 1

SAS - 12 Shotgun
This is the beefed up version of the Moss - 12 that you'll start coming across in later chapters. If you are a fan of the first shotgun, you'll love this one with its higher ammo capacity, faster firing and stronger blast. Just like the other shotgun, this is more useful on lower difficulty settings and when you're clearing a building with enemies at close quarters.
 * Clip: 8
 * Max ammo: 16

Handgun
Handguns are smaller and weaker than primary weapons, but allow for greater mobility while using them. You'll be able to shoot while hanging from ledges and other places, and you can use them with riot shields and propane tanks as well. In different places in the game, you may only have a handgun, so you'll be using them whether you want to or not. Beside the ones you can pick up during the game, there are two handguns that can be bought at the ../Store/. Choose your handgun based on what kind of effect you want to have: a fast-firing, large capacity gun for enemy suppression or a slower, more powerful gun for one-shot kills.

.45 Defender Semi-automatic Pistol
This is one of the standard pistols you'll find throughout the game, and features slightly more stopping power than the 9mms with slightly less ammo capacity. Accuracy is fairly good with this weapon, but don't be afraid to switch to one of the 9mm guns if ammo is lacking for the .45.
 * Clip: 8
 * Max ammo: 64

92FS - 9mm Semi-automatic Pistol
This ubiquitous weapon is found everywhere. Not a great amount of power, but decent accuracy and great clip capacity.
 * Clip: 15
 * Max ammo: 75

Chloe's .45 Defender
This weapon must be purchased from the ../Store/ to become usable. It's not much different than the other non-magnum handguns.
 * Clip: 7
 * Max ammo: 75

Desert - 5 Semi-automatic Pistol
Of the powerful handguns, the Desert - 5 is top tier. You'll get good ammo capacity, great accuracy and huge power. Except to get many one-shot kills with this weapon against normal enemies, especially with headshots. It doesn't have the max capacity of the weaker pistols, but is a great pairing with a high capacity primary weapon or the riot shield.
 * Clip: 7
 * Max ammo: 14

Eddy's Golden Gun
This is another weapon that must be purchased from the ../Store/ to use. Like the Desert - 5, this weapon has great power and accuracy.
 * Clip: 7
 * Max ammo: 14

Micro - 9mm Fully Automatic Pistol
This weapon can be compared to the standard uzi. It sprays a rapid volley of rounds and holds quite a lot of ammo as well. If you're prone to blind firing over cover or running-and-gunning, this is the spray-and-pray weapon for you.
 * Clip: 25
 * Max ammo: 125

P08 - 9mm
This old WWII weapon still works just as well as the other 9mm pistol. It has a slightly longer reload time, but it's still a standard weapon to go with and may be the only thing available on certain chapters.
 * Clip: 7
 * Max ammo: 56

Pistole Shotgun Pistol
If you were wondering why this weapon has such a loose aiming reticle, it's because it is a sawed-off shotgun. Like a shotgun this weapon has great stopping power, but don't expect to get accurately aimed headshots with it. Use this powerhouse if you know you're going into close quarters combat or in conjunction with the riot shield.
 * Clip: 2
 * Max ammo: 10

Tranquilizer Dart Gun
You'll only need to use this weapon on the second chapter, and it simply puts the enemy to sleep. You'll hopefully only be trying to use this from cover, so you'll have plenty of time to get the guard in your sights. Aim for the body instead of the head, as it's just as effective and less likely to miss. You only get one dart per clip, so try not to miss or you'll have to spend time reloading.
 * Clip: 1
 * Max ammo: 100

Wes - 44 Revolver
This is another of the "magnum" handguns, meaning it has tremendous power with little ammo capacity. This is a great weapon for taking down bad guys in one shot and using with the riot shield.
 * Clip: 6
 * Max ammo: 12

Other
The grenade is the only "other" weapon you actually carry with you, but there are certain other items you will find through the game that will lend assistance. It's a good idea to use these when they're presented, and sometimes it will be the only way to proceed. These besides the grenades, these items all have limits on either use or the ability to take them with you.

Mk-NDI Grenades
You'll get your first grenade in ../Borneo/, and they'll be constant companions throughout the rest of the game. The grenades will be indispensable in some situations where you need to clear a bunker or take out a group of enemies behind cover. You may be tempted to use grenades at times to destroy a large vehicle, but this is generally a waste of effort as there is always a more effective means to combat the armored opponent. You'll also want to avoid trying to catch fast-moving targets or single enemy targets. In the former case it will be hard to get the timing right, and in the latter, your grenade is better used to take out multiple enemies. You also don't have a great amount of range with the grenade, so become familiar with how far Drake can throw it before trying to lob it long distance.

Propane tank
The propane tank has much the same explosive properties as the grenade, but it is much harder to use. You'll start finding these littering the ground in Nepal, and they work well as makeshift bombs. Don't take your time throwing these over to enemies, as they're liable to shoot it while it's in your hand or right as you're throwing it, which only damages you. If you can, use these on unsuspecting enemies and make use of the quick-fire tap on psx: R1 to shoot it in air when it reaches the target. Carrying the tank around uses one hand, so your primary weapon won't be usable without dropping it, and you won't be able to do any heavy maneuvering (rolling, climbing) without dropping it as well.

Riot shield
The riot shield is a great way to approach enemies and take them out with your handgun. The bad part is you'll need to get it away from the enemy first. Riot shield users are most easily dispatched by blowing them up. Even if the damage isn't enough to kill them, they'll generally lose the shield when they go flying. The enemy will still be able to hit you while you're behind the shield, especially when you're aiming your gun, but it will provide some cover where there isn't any and when you need to be on the move.

Turret
At various points in the game you'll run into stationary turrets. Many times it's necessary to utilize the turret to progress, but every time is it highly recommended that you do so. For the machine gun emplacements that aren't required to be used, the scenario is generally such that when you take control of it, it helps to take out a new wave of enemies. Be aware of grenades being dropped in while you're behind the gun and be ready to leave off and dive away before returning to escape being blown up. The ammo capacity of the turrets varies, with some being unlimited for times when you have to use them, and the number depending on the difficulty lever for other. On Very Easy ammo is always unlimited, but on Hard the machine guns usually only have 200 rounds to spare.