The French DGSE agents, including Jean Reno as Agent Philip Roche, bring Heckler & Koch MP5A3 submachine guns with them when they infiltrate Godzilla's nest in Madison Square Garden (one of which has a Surefire flashlight grip). Some of the U.S. soldiers in the movie are also seen with MP5A3s.
The M16A2 is used by U.S. Army personnel throughout the movie to shoot at Godzilla (it is also possible that some of them might actually be M16A1s with M16A2 handguards, which is common in action movies from the 1990s). During the scene in the French DGSE warehouse, several agents are seen unloading crates full of these weapons and lying them on tables.
During the second scene in which Godzilla confronts the U.S. Army, several soldiers are seen firing M4A1 carbines at Godzilla, which have had their carry handles removed and replaced with C-More sights.
When Godzilla charges a U.S. Army roadblock, some of the soldiers are shown firing at him with, oddly, DAO-12 "Street Sweeper" shotguns, a weapon that has never been used by any branch of the U.S. military.
Some of the U.S. soldiers in the movie are shown using Defense Technology (DefTech) 37mm multi-shot launchers, including Doug Savant as Sergeant O'Neil. Some are also seen on a table in the DGSE warehouse where weapons are being unpacked. As in most Hollywood movies, the DefTech (and similar 37mm launchers) is inaccurately depicted as a weapon capable of firing HE grenades, whereas in real life it can only fire less-than-lethal ordnance.
Some of the U.S. soldiers in the film fire at Godzilla with M136 (AT4) rocket launchers. More are also visible in the DGSE warehouse where the weapons are being unpacked.
When the military has set its first trap and is waiting for Godzilla to show up, at least one soldier can be seen wielding a Franchi SPAS 15 combat shotgun, yet another weapon which is not used by the U.S. military.
