Beretta 92SB pistols are the sidearms of the SEAL team members in the film, although in reality the Beretta M9 was issued during the time the film was made. The Beretta 92SB was in fact issued to the United States Air Force until the M9 replaced that role as well.
Beretta 92SB Inox
Ramos (Paul Sanchez) carries a chrome-plated Beretta 92SB as a secondary weapon during the first raid. Somewhat unlikely since a SEAL team member would not carry a weapon that's so flashy in a night raid.
Beretta 92F
During a night raid, Ramos (Paul Sanchez) is seen using a Beretta 92F as noted by its squared trigger guard.
SIG P210
A terrorist used a SIG-Sauer P210 pistol to execute one of the American Helicopter Crewmen.
Skorpion SA Vz 61
A terrorist on the merchant ship holds a woman hostage with a Skorpion SA Vz 61 submachine gun, though it is never fired.
Heckler & Koch MP5SD3
Heckler & Koch MP5SD3s are used by the SEAL team throught out the film. They appear to be older model MP5SDs as noted by their smaller ribbing on the front grips.
Heckler & Koch MP5K
A Heckler & Koch MP5K is used by at least one of the SEALs during the hostage rescue mission, and later during a live fire training excercise.
Remington 870
Lt. Dale Hawkins (Charlie Sheen) uses a Remington 870 Police Magnum shotgun with a 12.5" barrel and black plastic pistol grip as his backup weapon and door breach gun.
Colt Commando
In several scenes some of the SEALs are seen carrying XM177E2 and XM177 carbines, notably during a training exercise and during the mission where Graham (Dennis Haysbert) is killed. Some of them are seen fitted with M203 grenade launchers. This movie is one of the very few films where we see an actual XM177 or GAU-5/A rifle (or a very close copy, being that the sound suppressor/flashhiders of the original XM177 were not good for blank firing guns, so many times an existing M16 rifle was custom modified to resemble the XM177. In the 1980s there were a slew of various aftermarket XM177 style flash hiders - some were very accurate, some were not.) At any rate, this is one of the most accurate portrayals of an XM177 in modern U.S. Cinema. The weapon is prominently displayed on the movie poster in the hands of Lt. Dale Hawkins (Charlie Sheen), fitted with an M203, although he never uses one in the film.
Barrett M82A1
A Barret M82A1 is used by Dane - call sign "God" (Bill Paxton), the SEAL team sniper to engage four targets during the hostage rescue mission and again during the Beirut mission. The weapon is outfitted with a Thermal Imaging Sight and Star Light. This could very well be the first film to feature the M82A1 model, as previous films had only utilized the cumbersome M82, such as RoboCop.
RPG-7
RPG-7s are used by the terrorists during the mission in Beruit. The rockets show two distinct paint schemes, a darker green paint job, flaking off showing the original yellowish/OD Russian paint underneath.
AK-47
Ben Shaheed's (Nicholas Kadi) militia use what look to be original AK-47s in the film. Many of them appear to be milled receiver AKs with Russian front sights and double tang back ends with the typical 'drop down' angled buttstock (with unique Type II Pattern stock mounting bracket) and the swivel sling on the body, not the stock. They could have been Poly-Technology Legend series of AKs that were imported during the 1980s (this movie was shot in 1989 and released in 1990). Since the sequence that was supposed to be Beirut was shot in Spain, the production could have used weapons provided by European Armorers (who at the time had no restrictions on acquiring Soviet/Russian guns).
AKS-47
An AKS-47 (also sometimes referred to as the AK47 Type 3B; Type 3 indicating type of receiver and B indicating folding metal stock) is used by the Christian Lebanese boy during the mission in Beruit. The underfolding AKS-47s in the movie are milled receiver Russian type guns, one of the few times we actually see real AK-47s (or really close copies) in a U.S. made film. Some of the SEALs guns change from AKMS's into AKS-47s due to continuity error.
AKM
Some of the terrorists in the film are seen using AKM rifles in the film.
AKM (mocked up as AK-74)
A terrorist is briefly seen using an AKM fitted with an AK-74-style muzzle break and using a bakelite magazine in an attempt to turn the weapon into an AK-74.
Norinco Type 56
Ben Shaheedis (Nicholas Kadi) is briefly seen firing a Norinco Type 56 (the Chinese version of the AKM) from one of the buildings.
AKMS
AKMS's are used extensively during the Beirut Mission by both the SEALs and the Opposition Force fighters, the AKMS is the underfolding version of the AKM rifle. These could be converted Maadi ARM/MISR rifles imported into the U.S. or real Russian rifles provided by European Armory houses for the filming in Spain.
Norinco Type 56-1
Lt. Dale Hawkins' (Charlie Sheen) AKMS changes to a Norinco Type 56-1 (the Chinese version of the AKMS) when he and the SEALs steal a citizen's Mercedes Sedan.
Chinese NMD-83
In the 1980s, there were two Chinese imported versions of the RPK (none of which looked very good).
Not to be confused with the Yugo RPKs imported by Mitchell Arms or the Maadi RPK clones, nor the Norinco NHM-91 which was a post 1989 import gun with a thumbhole stock and no barrel threads.
One of the pre-1989 ban guns was the NMD-83 - it had a 21" barrel, a standard AK stock and a muzzle brake (none of which was accurate for the RPK). They also imported a second RPK clone (whose name escape me) that had a Chinese style club foot stock but placed the bipod BEFORE (!!) the front sight, not after it, affixed to a long muzzle brake. This also looked atrocious and not many were sold. Not sure about the exact names of the Chinese RPK clones, since they didn't sell very well (hopefully someone who actually has a pre-1989 gun can let us know the exact name).
In the film, Leary (Rick Rossovich) carries what is supposed to be an RPK light machine gun. It appears to be a modified NMD-83 rifle converted to full auto fire. The barrel was lengthened from 21" to 23.25" which is more correct and the muzzle brake was removed. The short bipod was removed and a longer (though tubular, not rectangular) Chinese Bipod was attached (see pic). The Chinese Style front sight with the enclosed top hood was still used. Errors in the gun's modification are (a) the barrel is not an RPK heavy barrel but a long standard AK barrel, (b) The front foregrip is still a standard AK, in fact it's a Chinese Type 56 style, with the slot for the pig sticker bayonet, which is wrong, (c) the buttstock is the Chinese style clubfoot stock, not the thicker, more angular Russian RPK stock and (d) the receiver appears to be a standard Type 56 stamped receiver without the reinforcing bar of the RPK.