As you progress through the city of Rapture, exploration and events will yield weapons that will help you survive.
With the exception of the Wrench, each weapon has 3 different ammo types. The first is the standard ammo type, and then the second more powerful ammo types that have specific benefits. For example, the Pistol has standard bullets, Armor Piercing bullets, and Anti-Personal bullets. Try out different ammo as each one has its own special uses within Rapture. "Use the Directional Pad" to change ammo on your current weapon.
As you acquire more weapons, you can easily switch back and forth quickly by using the appropriate button or switching to the selection screen.
Each weapon can be upgraded twice using "Power to the People" machines found in Rapture. Think carefully on your upgrade choice as only one upgrade can be made at each "Power to the People" machine. Once the upgrade is made, the machine closes permanently. On the plus side, the upgrades are free!
 Weapons & Info
The wrench is the only melee weapon in the game and is also the first to be picked up. Being a melee weapon it does not require ammo so it can be used when ammo is scarce. The wrench is also the only weapon without any upgrades available, though it can be improved through the use of gene tonics, which can actually make it the most damaging weapon in the game per hit.
The pistol is the first gun found in Bioshock yet unlike pistols from many other games, remains useful throughout the game, especially when upgraded.
- Pistol Rounds
Standard pistol rounds are easy to find and deal a reasonable amount of damage to all targets, but not as much as the specialized ammo types.
- Armor-Piercing Pistol Rounds
Though harder to find than standard rounds, armour-piercing pistol rounds deal extra damage to armoured targets, like bots, turrets, cameras and big daddies, making them very useful.
- Anti-Personnel Pistol Rounds
Anti-personnel pistol rounds are the hardest to find, and are incredibly rare. They are so rare that the best way to get them is to invent them as they are never sold in vending machines. They deal extra damage against unarmoured targets, like any type of splicer.
- Increased Damage
This increases the damage dealt by all pistol rounds, making it more useful against the stronger enemies, especially later in the game.
- Increased Clip Size
This quadruples the clip size of the pistol from 6 to 24 rounds, so it doesn't need to be reloaded as often, negating one of the pistol's main disadvantages of the small clip.
 Machine Gun
The machine gun is the second firearm found in Rapture and strongly resembles a 1930's snail-drum Thompson submachine-gun, though it looks like it has been assembled from spare parts. The machine guns holds 40 rounds in a clip, which is needed as it has quite a high rate of fire. However, the high rate of fire means it is quite inaccurate and has severe recoil, making aiming during full-automatic fire difficult, though an upgrade will significantly reduce the kickback. The machine gun remains a useful weapon throughout the game, especially when upgraded with increased damage. It works very well against thuggish splicers, where accuracy isn't as much of a problem due the short range and is quicker than the shotgun, both in fire rate and reloading speed.
- Machine Gun Rounds
Standard machine gun rounds are easy to find and deal a reasonable amount of damage to all targets, but not as much as the specialized ammo types.
- Anti-Personnel Machine Gun Rounds
Though harder to find than standard rounds, they deal extra damage against unarmoured targets, like any type of splicer.
- Armor-Piercing Machine Gun Rounds
Armor-piercing machine gun rounds are the hardest to find, and are incredibly rare. They are so rare that the best way to get them is to invent them as they are only very rarely sold in vending machines, but they are always limited and hack-only. However, they deal extra damage to armored targets, like bots, turrets, cameras and big daddies, making them very useful, particularly big daddies, as the recoil and inaccuracy of the machine gun aren't as much of a problem due to the large size of the big daddies.
The Shotgun is the fourth weapon you receive in the game. It fires a wide burst of bullets and is most effective at short range. Effective against Splicers and Big Daddies.
There are three types of ammunition for the Shotgun:
- 00 Buck: The Standard Ammunition. Moderate damage and effective against splicers.
- Electric Buck: Fires bullets with electricity coursing through it. Has the same effect as Electro Bolt. Effective against Big Daddies.
- Exploding Buck: Fires bullets with fire coursing through it. Has the same effect as Incinerate. Usually sends splicers and Big Daddies up in flames.
Upgrades for the Shotgun:
- Rate of Fire Increase: Increases the rate of which you can fire the Shotgun. Useful because it takes awhile to fire the shotgun again.
- Damage Increase: Increases the damage dealt when using the Shotgun.
 Grenade Launcher
The Grenade Launcher is the 5th weapon you get in the game and is extremely useful especially against Big Daddies. It remains powerful throughout the game but isn't very good against Splicers.
There are three types of ammunition for the Grenade Launcher:
- Frag Grenades: The standard ammunition. Effective against Big Daddies and Splicers early in the game but is less useful later in the game.
- Proximity Mines: Mines that stick to the ground, wall, ceiling or large objects (eg. livesaver). When an enemy comes within range, the mine will detonate damaging anything within the area. Rosies also you proximity mines.
- Heat-Seeking RPG: Rather useful against enemies that move alot (eg. Spider Splicer). Follows an enemy and explodes within contact.
Upgrades for the Grenade Launcher:
- Damage Increase: The amount of damage dealt with the Grenade Launcher is increased.
- Damage Immunity: You will no longer be able to receive damage from the explosion of your Grenade Launcher bullets.
 Research Camera
This is used to obtain data on enemies, typically yielding damage bonuses against them, though sometimes Tonics, Plasmids, or in the case of the Little Sisters, EVE upgrades are obtained. It is found roughly 1/3 of the way through the game, in Neptune's Bounty. "Action shots" and "multiple subject shots" will yield greater research progress, as will use of the Photographer's Eye Tonics.
 Chemical Thrower
An effective weapon against any type of enemy. Obtained on the table in Langford's Office. There are three types of ammunition for the chemical thrower:
- Napalm: The standard ammunition. Useful against splicers and sets objects on fire.
- Liquid Nitrogen: Same effects as Winter Blast. Freezes enemies, including Big Daddies, so you can shatter them.
- Electric Gel: Same effects as Electro Bolt. Stuns enemies, including Big Daddies. While stunned, the damage done to the enemy is increased.
Upgrades for Chemical Thrower:
- Consumption Rate decreases - Uses less ammunition when spraying the Chemical Thrower.
- Range Increase - Increase the Chemical Thrower's very limited range
Highly effective against Big Daddies. Bolts (the crossbow's ammunition) come in three varieties: steel-tip (standard), trap (electric, can be used to trip up and shock enemies), and incendiary (explosive). You first get the crossbow from Sander Cohen after posting the photograph of Fitzpatrick's corpse for Cohen's masterpiece.
Upgrades for Crossbow:
- Damage Increase - Increase the amount of damage dealt using a crossbow. This is very useful because the Crossbow is already a powerful weapon, especially against Big Daddies.
- Breakage Chance Decrease - Lowers the chance a bolt breaks upon impact on an enemy or the environment. Useful for saving ammo.