Tugg Speedman (Ben Stiller), along with various other characters, uses a 16" barreled AR-15 Sporter II Carbine throughout the film, which is anachronistic for Vietnam . The original AR-15 Carbine was an SP1 (sold between 1978-1985)), so there was no forward Assist on the upper receiver. Stiller's gun is the A1 version, or what Colt called the "Sporter II version" in U.S. sales. The Colt Model 653 based weapons came after 1973. He should be using an XM177 variation to be accurate to the era. It may be an homage to the movie Platoon since the characters of Barnes (Tom Berenger) and Elias (Willem Dafoe) used the Phillipine export Colt Model 653 rifles. This film uses what is available in the United States, which happens to be the Sporter II carbine, since most of the movie was filmed in Los Angeles and Hawaii.
Kevin Sandusky (Jay Baruchel) and Alpo Chino (Branon T. Jackson) both carry M16A1 rifles fitted with the older style M16 muzzle flash reducers throughout the film.
The historical designation for the intermediate M16 between the original and the A1 was "XM16A1", which had the three-prong flash hider instead of the birdcage style. The prop guns used in the movie were M16A1s that were fitted with three-prong flash hiders by the armorer.
Jeff "Fats" Portnoy (Jack Black) wields an M60 Machine Gun as his weapon in the film. Jack Black commented on how he got stuck with the M60, which he knew was nicknamed "The Pig", and was tolds he was a natural with it, something he found disturbing. Some other random soldiers are also seen firing M60s during the opening scene.
One of the Guerillas is seen holding a Colt Gold Cup National Match 1911 pistol on Cody (Danny R. McBride) when he flies a chopper to their Heroin base and Portnoy is seen armed with it before Tran kicks it out of his hand, implying it is a rubber prop.
Lazarus is seen using an M1911A1 as his sidearm in the film and uses it several times. Portnoy later gets his hands on it and uses it to hold Tran (Brandon Soo Hoo) hostage.
Speedman and Portnoy are seen with M67 hand grenades attached to their belts and jackets. Since their film is supposed to take place in 1969, it makes sense to see them with these grenades, since '69 was when the M67 began to mass replace the M26 grenade.
M67 hand grenade.Error creating thumbnail: File missingSpeedman keeps an M67 grenade hanging from his jacket.Error creating thumbnail: File missingSpeedman pulls the pin on his M67 grenade to throw at the enemy guerrillas, and despite it being a dummy grenade, Cody happens to set off some C4 at the same time. This is a common 'cliche' in action films, especially bad action films, which is why Speedman does it. In real life, one cannot pull the pin from a grenade with one's teeth without causing severe dental damage.Error creating thumbnail: File missingPortnoy keeps an M67 on his belt.
During the opening "Hot LZ" scene, a Vietnamese soldier tries to throw a Vietnam Era Chinese Type II Stick Grenade at the Huey chopper as it takes off, so Speedman jumps up and stops the grenade, loosing his hands in the process. The "tin can" style Type II and the Pineapple style Type I stick grenades were commonly used by NVA (PAVN) soldiers or VC Guerrillas during the war.
North Vietnamese soldiers are seen armed with AKM rifles during the opening "Hot LZ" scene, one of which most notably disembowels Sandsuky with his bayonet. In real life, it would be more accurate for the Vietnamese to use Chinese Type 56 rifles, the Chinese copy of the AK (However, it is noteworthy that the NVA were receiving AKM rifles from the Soviets during the late 1960s/early 1970s so the use of the AKM in this scene is authentic to the period of time). Later the guerrilla soldiers can be seen armed with AKM rifles, which appear to be Egyptian Maadi ARM rifles, one of the most common AKMs used in films.
Several guerrillas, including Tran (Brandon Soo Hoo) are armed with AKMSU carbines modified with Krinkov parts kits with side-folding stocks and black furniture to resemble AKS-74U carbines.
Cody finds a Flamethrower, which looks like a modified M2, in the enemy shack. When he and Four Leaf Tayback (Nick Nolte) try to escape from the guerrilla's heroin base, Cody give Tayback the Flamethrower, which he uses to hold back the enemies.
Three types of M4A1 carbines are seen used by the guerrilla forces, one of which is seen with the carry handle removed, Knights Armament RIS rails affixed (with no rail covers) and fitted with a Aimpoint red-dot sight, the other with the carry handle attached with an ACOG scope mounted on it. Lazarus grabs one of these rifles and is seen using it when searching for Speedman in the huts, however his does not have the ACOG sight.
One of the guerrillas is seen armed with an CQBR rifle with an A2 receiver, and an ACOG scope mounted on the carrying handle. The CQBR is a short 10.3in. barrel version of the M4A1 Carbine, so it certainly fits the profile.
Tran uses a Norinco Type 69 RPG launcher to take out the truck the gang tries to escape in and tries to shoot down their chopper as they escape, the rocket being stopped only by a perfectly thrown TiVo box from Speedman's agent, Rick "Pecker" Peck (Matthew McConaughey).
