The following weapons were used in the film Blood Diamond:
At the beginning of the film, Danny Archer (Leonardo DiCaprio) carries a sub-compact Glock variant, which is most likely a Glock 26 and hands it over when stopped by Commander Rambo (Ato Essandoh). The Glock is loaded with what appears to be an extended magazine. Archer later has the pistol confiscated when he is arrested for smuggling diamonds into Liberia.
Heckler & Koch USP Compact
A Heckler & Koch USP Compact is used by Danny Archer (Leonardo DiCaprio) throughout the film. He purchases this weapon from his friend, M'Ed (Ntare Mwine), at a bar for a couple hundred dollars after having his Glock 26 confiscated while smuggling diamonds. Archer claims that he wants "the best [he] can get ahold of" and M'Ed says he will find him "something special". Once he gets the USP Compact, Archer uses it to kill several R.U.F. rebels and a few of Col. Coetzee's men. Near the end of the film, Archer gives the pistol to Solomon when he tells Solomon that he will stay and hold off Col. Coetzee's men so Solomon can make his escape.
The film takes place in 1999, and the USP Compact had just been introduced in late 1996, so at the time the pistol would have been relatively new and maybe even rare. The USP series is also globally renown for its reliability, so it was definitely what Archer was looking for. Several close-ups of Archer's USP Compact reveal that it has an exposed hammer (the Compact, unlike the full-size USP, does not have a spurred hammer as standard), which suggests the gun might be the P10 variant, or otherwise a specially modified weapon. The USP Compact is also seen on the cover of the film's home video release.
Heckler & Koch USP
Full-size Heckler & Koch USPs are carried by South African mercenaries, most notably Colonel Coetzee (Arnold Vosloo). Coetzee's USP is later picked up by Dia Vandy (Kagiso Kuypers), the son of Solomon Vandy (Djimon Hounsou).
Smith & Wesson Model 629
Commander Rambo (Ato Essandoh) of the R.U.F. wields a variant of the Smith & Wesson Model 629 revolver when he confronts Archer and demands his weapon. There is a slight possibility the revolver could be a Smith & Wesson Model 686, however the barrel looks about 5" which would likely make it the 629 model.
Chamelot-Delvigne Model 1873
A Kamajor guerrilla points a French Chamelot-Delvigne Model 1873 11mm revolver at Solomon and Maddy Bowen (Jennifer Connelly) while thinking they are R.U.F.. Note the revolver may be a Model 1874 which is the same gun with a fluted cylinder.
Near the end of the film, some of the mercenaries carry IMI Uzi submachine guns, though they are hard to see.
Several Sierra Leone Army soldiers can be seen carrying Sterling L2A1 submachine guns during the scene where Archer is arrested for smuggling diamonds. Some guards at the prison in Freetown also hold Sterling L2A1s.
Colt CAR-15 variant
South African mercenaries carry an unusual Colt CAR-15 variation that does not appear to be a factory-standard gun. These rifles have the receivers of M16A2s (which would normally suggest Colt Model 725s), but they also have 10-inch barrels with GAU-5/XM177-style flash-hiders. They were most likely custom-assembled for the film from the parts of various AR-model rifles. It should be noted that similar rifles can be seen in Black Hawk Down, and Bapty & Co. supplied the weapons for both this film and that one.
Besides their unusual combination of features, the mercenaries' CAR-15s also feature camouflage paint and accessories such as Surefire 660 weaponlights and Aimpoint CompM2 red dot sights. Near the end of the film, Archer uses one after killing its owner, buying time for Solomon and Dia to escape before succumbing to his wound.
Norinco Type 56-1
The vast majority of the Revolutionary United Front (R.U.F.) rebels and Sierra Leone Army soldiers are seen using Norinco Type 56-1 assault rifles (Chinese AKS-47/AKMS clones), which can be recognized by their folding stocks and hooded front sights. Archer briefly uses one to execute an R.U.F. rebel who tries to flee him on the bridge. Dia can be seen using one while participating in his first massacre as an R.U.F. member (he is also forced to use one to kill a prisoner while undergoing indoctrination).
There are also some original Russian-made AK-47s (as opposed to AKM copies or Chinese Type 56s, which are far more common in most Hollywood films) seen in the hands of R.U.F. rebels throughout the film. Most of them are the Type III milled receiver variation, but a close-up of one of the AKs reveals that it has the stock mounting bracket of the slightly older Type II variant. The child soldier who tries to kill Benjamin Kapanay (Basil Wallace) uses one, and Archer also wields a Type III AK-47, which he uses to kill a few of the rebels during the mercenaries' assault on the mine.
Heckler & Koch G3
Many of the R.U.F. rebels and Sierra Leone Army soldiers are seen carrying older-specification Heckler & Koch G3s with wooden handguards and stocks though without seeing the rear sight. This is quite true to real life, the G3 was standard-issue to the Sierra Leone Army for many years (though they later began purchasing Type 56 rifles from the People's Republic of China), and many fell into the hands of the R.U.F. during the civil war.
Several Sierra Leone Army soldiers can be seen with M16A2 assault rifles, and many of the South African mercenaries use them as well.
Lee-Enfield No.1 Mk III
One of the Kamajor guerrillas that surprises Archer's group carries a Lee-Enfield No.1 Mk III with a rag wrapped around the rifle.
Throughout the film, DShK heavy machine guns are seen mounted on the R.U.F.'s "technical" vehicles.
Near the end of the film, a few of the mercenaries' Land Rovers have Browning M1919A4 machine guns mounted on them.
One of the Kamajor guerrillas carries a Browning M1919A6. Although the full stock is never seen (only the grip), the muzzle booster on the weapon proves that it is an M1919A6. The bipod fitted on the M1919A6 was also (fittingly) fitted on the M1918A2 Browning Automatic Rifle.
The Sierra Leone Army uses a number of .50-caliber Browning M2 heavy machine guns, which are mounted on many of Land Rovers throughout the film.
Near the end of the film, a mercenary sitting on a Land Rover holds what appears to be an FN Minimi.
A PKM machine gun can be seen mounted on the door of the mercenaries' Mil Mi-24 "Superhind" helicopter and is fired by one of them.
During the scene where Archer and Solomon are crossing the bridge, an RPK light machine gun can be seen leaning against a wall at the R.U.F. guard post.
R.U.F. rebels regularly wield RPG-7s, particularly during the battle of Freetown. One rebel also fires one at Archer and Maddy's vehicle during the press convoy ambush, but misses.
GIAT F2 20mm Cannon
The helicopter used in the assault appears to be the Mil Mi-24 "Superhind". The "Superhind" is a modified model of the original Mi-24 made by the South African company "Advanced Technologies and Engineering" (ATE). All the "Superhinds" carry the French GIAT F2 chin-mounted 20mm cannon.