A Marine at the funeral during the opening credits can be seen briefly holding an M14 rifle.
Beretta 92FS
The Recon Marines carry Beretta 92FS (military designation, M9) pistols as their sidearms. Beretta M9s are the standard side arm for all the Navy SEALs including Stanley Goodspeed (Nicolas Cage), all with tactical flashlight attachments. Goodspeed points his at John Mason (Sean Connery), who swipes it out of his hand, but later gives it back to Goodspeed to defend himself with, and he uses it notably in the underground tunnels to kill one Marine, with little hesitation, as Mason notes.
Beretta 92FS Inox
Major Baxter (David Morse) uses a Beretta 92FS Inox as his sidearm. He draws it on Hummel before turning the gun on Darrow and firing at him before being gunned down by the other Marines.
Beretta 92SB
One of the Marines, Captain Darrow (Tony Todd) is seen using an older 92SB (which has a rounded trigger guard, rather than squared, like on the 92FS/M9) with wood grips during the scene in which Hummel and his men use a hostage to draw Goodspeed and Mason out of hiding.
I might be wrong, but I don't think this is Captain Darrow holding this gun. I think it's the other big black guy, the one who tells Goodspeed, "I'd take pleasure in guttin' you, boy" after he gets captured, and who attacks him with the M60 at the lighthouse. Whoever it is has HUGE hands, as you can tell by the fact that there isn't enough space on the grip for his pinky. -MT2008
Beretta 92FS Centurion Inox
During the hotel scene Goodspeed is given a Beretta 92FS Centurion Inox by another FBI field agent after he arrives in San Francisco and tells Womack (John Spencer) that he forgot his FBI-issue sidearm.
M16A2
Marines at the funeral use real M16A2 rifles for the 3 volley salute.
M16A1 (w/ M16A2 handguards)
Many of the Marines under General Hummel's (Ed Harris) command are armed with M16A1 assault rifles fitted with M16A2 handguards. They are easily noticed as A1 models by the lack of a brass deflector and elevation-adjustable rear sight, older forward assists, and fully-automatic firing modes. Most of them have tactical flashlights installed on the barrels.
Colt Commando variants
Colt CAR-15 Commando look-a-like rifles seen being used by many of the Marines. Mason and Goodspeed take two for themselves later in the film. The Commandos in the film all have 10" barrels and older-style flash suppressors, but also have various receiver styles. Some have A1 receivers, others have A2 receivers, and others have the forward assist and brass deflector but not the A2-style rear sight. Some have tactical flashlights on the barrels.
A notable goof is that the receivers of the guns held by individual characters change throughout the film (for instance, the Commando handed to Goodspeed by Mason clearly has an A2 receiver when he first gets it, but later, it has an A1 receiver).
Actually, Darrow's gun changes a whole bunch of times. Sometimes it's an A1, sometimes it's an SP1, and then just before he throws it down in the lighthouse, it's actually an XM177 with an M203. Also, several of the other Marines can be seen using XM177 look-a-likes with M203s. -MT2008
Really? I thought he had an M16 in the lighthouse as well, but they didn't give me a lot of good shots. I'll look back at it. - Gunmaster45
MAC-10
Hummel can be seen holding a MAC-10 in a Vietnam service picture. This image is actually taken from one of Ed Harris' earlier film roles, the Charles Bronson vehicle Borderline.
Colt M1911A1
The main villain of the film, General Frank Hummel (Ed Harris) carries a stainless Colt M1911A1 as his sidearm of choice throughout the film. It is seen being pulled out by Hummel, who then shoots Sergeant Crisp during the confrontation.
Heckler & Koch MP5A3/A5
Heckler & Koch MP5A3 submachine guns are used by the Navy SEALs during the failed rescue mission of the prison. They have Surefire dedicated forend weaponlights. Mason wields an MP5A3 he commandeers from a dead SEAL, and uses it in the first half of the movie.
A handful of the MP5s used by the SEALs also appear to have the 4-position trigger group (for safe, semi, 3-round burst, and full-auto) and smooth lower reciever, which makes them MP5A5s rather than A3s.
A SEAL can be seen using a shortened tactical Remington 870 shotgun.
Heckler & Koch SP89
A Heckler & Koch SP89 by one of the SEALs during the failed attempt to save the hostages. It seems to be fitted with the collapsible stock of an MP5A3, and was evidently converted to full-auto.
DefTech Launcher
What appears to be a Defense Technologies (DefTech) 37mm launcher is used by Private McCoy (Steve Harris) in the shower room, firing shotgun like rounds at the Marines. They could also be Hornet's nest rounds, which is a grenade round with 8 .22 long rifle bullets inside.
M26 Handgrenade
Cpt. Frye (Gregory Sporleder) can be seen with two M26 hand grenades which he throws at Mason (Sean Connery) in an attempt to kill him. Mason jumps into a bathtub to avoid the blasts.
M60E3
A Marine can be seen firing an M60E3 machine gun at Goodspeed when he disables the last rocket. Mason picks it up and knocks the shooter off the roof with it.
LAR Grizzly Big-Bore
When the Marine's M60E3 is empty, he picks up a .50 BMG LAR Grizzly Big-Bore bolt-action rifle to shoot Goodspeed. He is knocked off the roof by Mason before he can use it, though.
"The Protector"
When Goodspeed is messing around in his office, he shoots a flip down target with a suction dart spring gun labeled "The Protector". It appears to be based off a Mossberg 500 "Cruiser" with barrel ribbing.