The following firearms were used in the movie War, Inc.
War, Inc. follows PMC employed Hauser(John Cusack) who is tasked with assassinating the leader of the fictional country of Turaqistan: site of the first war to ever be 100% outsourced to Private Military Companies.
Hauser's(John Cusack) primary weapon is a Walther P99, and frequently two at once. He uses a P99 with a suppressor and laser sight to assassinate the three German men in Canada as the film opens. He later uses them in a shootout with Tamerlane shock-troops. Hauser seems to have problems with his P99s, as the slides never lock back when empty, constantly surprising him in the middle of firefights.
Beretta 92FS
Hauser and Walken are both initially armed with Beretta 92FS handguns in flashback scenes. Ooq-Mi-Fay Taqnufmini is also armed with a Beretta 92FS with stainless slide, which he memorably shoots himself with when trying to tuck it into his pants. Later on at the wedding, Natalie takes Ooq-Mi-Fay's Beretta and holds it threateningly.
Taurus Model 85
One of the men who takes Natalie Hagelhusen's camera crew hostage is armed with a stainless steel Taurus Model 85.
Uzi
The Uzi is first seen in the hands of a thug working for Ooq-Mi-Fay, but is commandeered by Yonica Babyeah(Hilary Duff), who initially holds it by the stock.
Steyr AUG
Hauser has a Steyr AUG A2 with special camera-scope that he attempts to use to assassinate the Turaqi Sheik. The barrel has a custom flash-hider that imitates the Barett M95, and is controlled remotely via joystick from Hauser's HMMWV.
AK-47
Many different AK-47 variants are seen in the hands of Tamerlane soldier, Shock Troops, and rebellious Turaqi militia. Typically the Turaqi militia are armed with older AK-47 and Norinco Type 56 models, whereas Tamerlane employees are armed with AK-103s instead. A few Tamerlane soldiers are armed with AKMS rifles, but these are never seen fired and it is likely they are airsoft replicas.
GE M134 Minigun
A GE M134 Minigun is mounted on top of the tank that delivers Hauser's dry cleaning.