Resident Evil Zero

Beretta 92F Mod. Samurai Edge

Rebecca Chambers and the members of S.T.A.R.S. Bravo team carry customized Beretta 92F pistols known as Samurai Edges. During the course of the game, you can find extra parts to customize this weapon with a scope. This upgrade dramatically improves your chance to land critical shots on the enemies.

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"A custom handgun that has been fitted with a scope for greater accuracy. These modifications should make it easier to hit a target's weak point."

"Army Handgun"

Billy Cohen uses this handgun. It's a 9mm, holds 15 rounds and is apparently standard issue for US Army. The design is fictional, and features a beretta-style cutaway slide.

Over and Under Shotgun

Found on the train.

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"A shotgun used for hunting. There's a design carved on the barrel. This model can only be loaded with 2 shells."

Remington 870

Remington 870 Wingmaster. Found in the mansion. In-game the capacity is 7 rounds firing 12 Gauge cartridges.

Remington 870 12 gauge

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The petite Rebecca Chambers (in bonus costume) carrying the Remington 870

SMG

Unlocked after beating the game. Not sure what this one is. A modified MP5, maybe?

It just resembles an MP-5

It looks like a HK54 with various prop parts added

The weapon is (supposedly) made by (an) Umbrella (subsidiary - in apocryphal literature, the company was called Sporting International), just like the semi-auto Magnum and the Pump Shotgun. This was the game designers' way to avoid copyrights.

"A small sub-machine. It uses it's own type of ammo magazine."

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Billy (in bonus costume) with the unlockable SMG.

Arwen 37

The Grenade Launcher resembles a Arwen 37

Arwen 37 37mm

"A large grenade launcher featuring a revolver-style chamber."

Magnum

A .50 that holds 6 rounds. It's powerful enough to kill virtually any enemy in one shot, and is very effective against bosses.

"A large handgun capable of firing powerful magnum rounds."

Taurus Raging Bull

This magnum is unlocked after completing the Leech Hunter mission.

Taurus Raging Bull .44 Magnum

"A magnum revolver containing enhanced parts like a new cylinder and frame. It's tremendous firepower makes it more of a hand cannon than a handgun."