There are many weapons in the multiplayer of Red Dead Redemption. They can be unlocked by ranking up.
Pistols and Revolvers
Cattleman Revolver
The Cattleman Revolver is a general-purpose revolver available to the player from the start of multiplayer.
Volcanic Pistol
The Volcanic Pistol is a pistol available to a player at Rank 5. It is a fairly weak pistol compared to others, and has a low fire rate, but causes sufficient damage to be able to kill enemies in two or three shots.
Schofield Revolver
The Schofield Revolver is a single-action six-shot revolver, available to a player from Rank 9. It fires a powerful .45 round and is effective at killing enemies quickly.
Double-Action Revolver
The Double-Action Revolver is a revolver available at Rank 17. It can fire at a much faster rate than a standard revolver, but at a reduced accuracy. It has a medium clip-size.
Projectiles
Dynamite
Dynamite is an explosive available to the player from Rank 15. A player can carry a maximum of two sticks at a time. When using dynamite, the fuse is automatically lit whilst the player is aiming the projectile, leaving it prone to explode in the player's hand if it is not thrown within a time limit. It has a moderate blast radius and is useful for killing many enemies in one place, for example those entering through a door.
Fire Bottle
Fire Bottles are projectiles which explode into flames on impact. They are unlocked to a player at Rank 22, and a player can carry a maximum of two of them at a time. They do not kill a player, instead knocking them to the floor for several seconds and reducing health. They are often used by reinforcement NPCs when clearing a gang hideout.
Throwing Knife
Throwing Knives are available to the player from Rank 3. They are small knives which can kill a player in two hits. A player can carry twenty of them at a time.
Shotguns
Rifles
Rifles are single-shot weapons which are fairly accurate and have moderate range.
Repeater Carbine
The Repeater Carbine is the first rifle the player unlocks in multiplayer mode, at Rank 2. It is a short rifle which is effective when the player is on horseback.
Scoped Rifles
Other
Hunting Knife
The Hunting Knife is a melee weapon available from the start of multiplayer. It inflicts major damage to animals and can be used in combat to seriously damage another player.