Billy (Sonny Landham) and Dutch (Arnold Schwarzenegger) are prominantly seen armed with AR-15/SP1 slab-side M16 rifles fitted with M16A1 birdcage muzzle flash suppressors to apear more modern (they are likely AR-15/SP1s over genuine M16s, converted to full-auto by the armorers for the film). Dutch's AR-15/SP1 is fitted with an Fake M203 Launcher and a perforated forend typical for the M203, while Billy's AR-15/SP1 is fitted with a Mossberg 500 shotgun and M16A2 foregrips. These particular SP1 rifles are clearly fitted with blank adapters (which are visible sticking beyond the muzzle, out into the flash hider), which means they were real guns converted to fire blank rounds. Many other guns in the movie also have these adapters visible.
Fitted on Dutch's AR-15/SP1 is a Fake M203 Launcher with a 39mm bore diameter. This particular faux launcher was popular at the time before the Cobray launcher was produced and was used in several other '80s movies, including Heartbreak Ridge. Gun gun is innacurately seen capable of detonating its rounds at close range, yet real M203 rounds have a safety device in which they must spin for a certain amount of time before detonating, giving it a range limit. Dutch later uses his spare 40mm rounds (which actually don't fit his launcher) to make explosives to face the Predator.
Billy's AR-15/SP1 is fitted with a Mossberg 500 underslung under the barrel. While never seen firing the shotgun in the film, he is seen pumping it closed after the men cut down the forest with weapons fire, implying he had been firing it during that scene. In the original screenplay, Billy's SP1 rifle was to be fitted with an M203 launcher. During the helicopter scene, he was to be seen opening and closing the breech repeatedly. Since the fake M203 launchers don't open in such a matter, I guess someone decided to change it to a Mossberg 500 shotgun (although they seemed to have forgotten the helicopter scene).
An M60E3 machine gun is carried by Sgt. Mac (Bill Duke). Like the gun in Commando, this M60 appears to hav a professionally shortened barrel. They actually could be the same gun supplied by Stembridge Gun Rentals.
Nicknamed "Ol Painless", a hand-held M134 Minigun is the main weapon of the movie carried by Blain (Jesse Ventura). It has been modded for Commando use with an M60 handguard and a rear pistol grip. The weapon was powered by an electric cable hidden in the actors pants and fired reduced power 7.62x51mm blank rounds to ease the recoil force. It is believed in real life a similar weapon was tested by US special forces in the 1970s but found impractical (This statement is false, anyone with the least bit of knowledge about this weapon system would know that a soldier cannot fire a multi barreled 7.62mm machine gun, since the recoil would equal the same G-force as trying to lift a 350lb football player.). Although rumoured to be an XM214 'Microgun' which fires the smaller 5.56mm NATO rounds, it is the larger M134 hence the barrel cluster. The gun is also operated in the film by Mac shortly after Blain's death and Mac uses it to chop down half the forest in an attempt to kill the Predator.
An interesting note, after Mac fires the Minigun and chops down half the forest, he claims he fired off 200 rounds, a full pack. With what Blain and Mac had fires combined, it is more like 2000 rounds.
The Heckler & Koch HK94 are the mainstay weapons of many members of the squad. Blain (Jesse Ventura), Poncho (Richard Cheves), Hawkins (Shane Black) and Dillon (Carl Weathers) all carry them. The guns are meant to be MP5A3s, but close inspection reveals they are the civilian HK94s with the 16" barrels chopped down and they are converted to full auto. They clearly aren't MP5A3s do to the lack of the three lugs on the barrel, the lack of the paddle magazine release situated behind the magazine, under the gun. They also lack the push pin set.
Sgt. Mac can be seen arming M18A1 Claymores as part of the defensive perimeter when he and the commandos camp out for the night after Blain is killed, then when Dutch orders the other commandos to make a stand against the Predator in the jungle. Mac and Blain are also seen disarming a Claymore when they sneek into the Guerilla camp.
One of the Guerillas is seen using a Walther PP to execute an American prisoner. Anna (Elpidia Carrillo) is also seen trying to shoot Dutch with a Walther before he whips around and rifle butts her.
Billy, Dutch, and Mac are also seen with IMI Desert Eagle handguns, presumabley .44 or .357 Magnum, holstered as their sidearms. Dutch keeps his in a hip holster while Billy and Mac use shoulder holsters.
Some of the Guerillas are seen armed with Valmet M78 light machine guns, note by their synthetic "Dragunov" style stocks. While similair to an RPK machine gun, slight diffrences in the sights and reciever help tell them apart.
Dutch can also be seen wearing a few M67 Grenades on his vest at the beginning. These grenades are also thrown around by the various commandoes during the raid to the guerilla base. Satchel charges are also used by Dutch to blow up a pickup truck after he manages to make it fall through a wall and right into a small gathering of the guerillas.
