Captain Munro Kelly (Ernie Hudson) carries a Custom M1911A1 Pistol with an extended target front sight, a Bomar Rear Sight and a Safari Arms Ambidextrous Safety.
M60 Machine Gun
An M60 Machine gun is briefly seen during the escape attempt from the Mwanzaa Airport - 7.62x51mm
MG34
During the same sequence an MG34 is also seen being wielded by a junta soldier - 7.92mm
MP40
During the negotiations after their arrest, a junta soldier is seen threatening a man with an MP40 submachine gun - 9mm.
Soldiers at the Mwanzaa Airport carry either Russian AK-47 rifles or Poly Tech Legend AK-47 Rifles. They are the classic AK design without the Chinese Type 56 Style hood.
Norinco Type 56 rifle
Junta soldiers prior to their entry into Tanzania (and then into Zaire) also carry Chinese Norinco Type 56 rifles - the Chinese AK47 copy.
A full auto Rocky Mountain Arms Patriot Pistol is seen being loaded by Kelly's men prior to the night battle and Dr. Karen Ross (Laura Linney) ends up using it during the fight. The pistol is built up from a Patriot barreled Upper receiver on a full auto Colt XM lower (possibly a Model 614 Export version), which has a partial magazine fence as opposed to the "slab side" receiver found on the SP1 Sporter. Rather than use the short buffer tube on most AR15 pistol variants, the armorers simply removed the XM177 style buttstock from the standard Carbine Buffer tube and kept it on the firearm. The finishes are noticeably different from the Patriot upper receiver and the Colt Lower receiver. These custom firearms appear to have also been used in 1998's Soldier.
Dr. Karen Ross (Laura Linney) carries and uses an Uzi Submachine gun during the final battle. The Uzi is later used by Dr. Peter Elliot (Dylan Walsh).
Unknown Bolt Action Rifle
I'm leaning towards a Winchester Model 70 without a scope due to the general shape. A background Kelly man holds a bolt action rifle but never fires it. Facing a horde of attacking Grey Gorillas one would want an assault rifle at the least.
Sentry guns
Similar to the sentry guns used in the director's cut of the film Aliens, the camp has machine guns with dual drum magazines operating automatically to fire at movement 'out to 40 yards'. Though the sentry guns in Aliens were actually German MG42 machine guns, these are fake acetylene gas firing mockup guns. In the book, they also had sound suppressors, which had to be taken off to scare off the gorillas.