In the film, the War Machine armor worn by Col. Rhodes (Don Cheadle) is outfitted with several weapons including:
M134 Minigun
When Justin Hammer (Sam Rockwell) is asked by Col. Rhodes (Don Cheadle) to weaponize the Mark II Iron Man suit, he presents several weapons for them. One of the main weapons Hammer displays is the M134 Minigun. 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 even though more than 100 lbs with all the parts, but the barrel unit is light enough to pick up. The "War Machine" has the M134 mounted on its right shoulder.
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".
SHIELD Agent 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.
The Army version of the Hammer drone is seen armed with a large single barrel cannon, which according to director Jon Favreau's audio commentary, is based off the 25mm M242 Bushmaster chaingun.
