In the film, the War Machine armor worn by Col. Rhodes (Don Cheadle) is outfitted with several weapons including:
M134 Minigun
The M134 Minigun is seen shoulder-mounted on the War Machine suit. Hammer says that the boys in uniform refer to it as "Uncle Gazpacho" or "Puff the Magic Dragon" when showing it to Rhodes, and correctly identifies it as a 7.62mm. He also picks it up with ease. The minigun weighs more than 100 lbs and would be hard without help. You sure? It's tiny. Maybe with all the parts, but the barrel unit is light enough to pick up
The FN F2000 assault rifle is also mounted on War Machine. Referred to as the FN 2000 by Hammer also seen showing it off to military personnel(Sam Rockwell)
The Milkor MGL is another weapon of War Machine. The desert tan series of Iron Drones also have one built-in to their right forearm. It is also one of the weapons Hammer presents for "crowd control" or "hippie control".
Natasha Romanoff (Scarlett Johansson) carries a H&K USP Compact which she wields along with a Walther PPK/S when she goes to Hammer Industries, she gets it from a guard after disarming him.
Carried by US Air Force Security Forces airmen with flashlights, foregrips, and sights, most notably when Lieutenant Colonel Rhodes arrives at the base half-way through the film.
Error creating thumbnail: File missingColt M4A1 Carbine with M68 Aimpoint reflex optic and Knight's Armament RAS railed handguard and vertical forward grip - 5.56x45mm
Walther PPK/S
Natasha Romanoff (Scarlett Johansson) carries a PPK/S .380acp pistol in a side holster. It looks Stainless and its in a Blackhawk Serpa Holster.
