Edward Carnby (Christian Slater) carries a Colt Anaconda (.44 magnum) as his primary sidearm.
Colt M4 Carbine
The primary weapon of the Bureau 713's commandos is the M4 Carbine, outfitted with RIS rails, a flashlight and laser, usually fitted with an Elcan Optical sight on the receiver's flat top and an unusual custom sci-fi designator on the foreward grip top rail.
M16A3
Mixed in with the M4 carbines, are M16A3 full sized full auto rifles.
M60E3
One of the Bureau 713 commandos is seen prepping an M60E3 for the final assault.
GE M134 Minigun
Set up like 'smart guns' from films like Aliens and Congo the miniguns are set to fire at anything moving within 50 feet (since past 50 feet are another barrier and past that are the trip wire mines). Unfortunately, the Zeno creatures phase in and out of our dimension so they're hard to hit.
Browning M2HB
Beretta Inox
Calico M-951A Automatic Rifle
Mixed in with the M4 Carbines of the Bureau 713 commandos are a number of Calico M-951A Full auto rifles (not the 955A since these rifles have full length barrels). These 951A rifles are outfitted with M900S Full buttstocks (an easy swap out). They have Calico style scope mounts and short optical scopes as well as Flashlights, foregrips and the same custom IR designator as seen on the M4 Carbines.
20mm Auto Cannons
Trivia
Firefight
For a bad Owe Boll film, the battle between Bureau 713 commandos and the Zenos is pretty good. The Special effects are nice, though the editing is schizophrenic. Too much speed metal rock music and 'shaky cam' editing, but there are good gore effects and the Zeno monsters are an example of good CGI (in comparison to the cheap CGI seen so often on movies 'made for the Sci Fi Channel').