Raza's Ten Rings fighters carry Heckler & Koch G36K assault rifles, most fitted with G36C-style carry handles. In the film, Tony Stark (Robert Downey Jr.) learns that Obadiah Stane (Jeff Bridges) had been secretly selling Stark Industries weapons behind his back to the Ten Rings as part of Stane's attempts to take over Stark Industries, making them better armed than any of the other militant factions in Afghanistan and Pakistan. The various assault weapons used by Raza's men, including the H&Ks, are therefore supposed to be Stark Industries products. It is also possible that in the Marvel universe, Stark Industries obtained a license from Heckler & Koch to produce G36 and UMP-series weapons in the U.S. Or that Stark industries has bought Heckler & Koch.
Heckler & Koch G36C
Several of Raza's men are also armed with the compact version of the G36, the Heckler & Koch G36C. The G36's are also outfitted with many accessories to disguise their origins. During the escape from the Ten Rings' camp, Yinsen (Shaun Toub) grabs a G36C dropped by one of the fighters and runs towards Raza's men firing wildly, trying to divert attention from Stark until the suit is powered up and he can use it to fight his way out.
Heckler & Koch AG36
Raza (Faran Tahir) is seen with a H&K G36K fitted with a Heckler & Koch AG36 grenade launcher, which he fires at Stark in the prototype Iron Man armor, but misses and is knocked out by Stark's missile instead.
Heckler & Koch UMP45
Several of Raza's men are armed with the .45-caliber version of the Heckler & Koch UMP with tactical outfitting.
SIG SG 552
One of Raza's men is seen armed with a SIG SG 552 with tactical outfitting.
M4A1
USAF Airmen stationed in Afghanistan are seen armed with M4A1 carbines. They are also used by airport security when Tony Stark returns to the United States. The M4A1's in the movie are equipped with Insight Technologies ISM-V scopes; These scopes have built-in laser aiming modules and night-vision, thus eliminating the need for anything but the handgrip.
M26 Modular Accessory Shotgun System
Held by one of Raza's men is an M4A1 with a Magpul Buttstock and an M26 Modular Accessory Shotgun System (MASS) fitted under the barrel. The image seen below is a heavily edited clip that is included on the U.S. version of the trailer. The M4 with M26 is put in to replace another shot of the weapon that is pointed at Tony Starks' head. The MPAA doesn't allow trailers to show any weapons to pointed at a person, even if that's how the final cut shows it. This seems to be a fairly common practice as evidenced in the trailers for Indiana Jones and the Kingdom of the Crystal Skull and Cop Out.
When Stark is giving his presentation of the Jericho missile, a row of Mk 46 Mod 0 Light Machine Guns are seen on a table.
FN M240B
USAF Airmen in Afghanistan used FN M240B machine guns mounted on top of their Humvees.
Browning M2HB
Both Ten Rings fighters and USAF Airmen in Afghanistan can be seen using the Browning M2HB 50-caliber machine gun. The Ten Rings fighters place the machine guns in their camp, with the USAF Airmen have them mounted on top of their Humvees.
IMI Galil MAR
One of Raza's men is seen armed with a IMI Galil MAR, the most compact version of the Galil assault rifle.
Heckler & Koch USP
One of the Ten Rings members attempts to shoot Stark in the head with a Heckler & Koch USP when his arm gets stuck in the wall, but the round deflects off the armor and hits him instead. Abu Bakaar (Sayed Badreya), the leader of the Ten Rings guerrillas is also seen with a USP at his hip in a holster.
Glock 17
The SHIELD agents escorting Pepper Potts (Gwyneth Paltrow) to arrest Obadiah Stane (Jeff Bridges) are armed with Glock 17 pistols, which they fire at Stane, now "Iron Monger", but prove useless and they are easily dispatched.
FGM-148 Javelin
FGM-148 Javelin missile launchers can be seen in the Ten Rings' camp.
BGM-71 TOW
BGM-71 TOW missile launchers can be seen in the Ten Rings' camp.
M134 Mingun
In the ending credits there's a drawing of character, that will appear only in Iron Man 2 -War Machine with M134 Minigun mounted on the shoulder of his armor.