The following weapons in this film are:
M1911A1
Used by Mason Storm (Steven Seagal).
M16A1
Colt XM177
Heckler & Koch MP5
Heckler & Koch MP5A3 - 9x19mm
Ruger AC556
Ruger AC556 Carbine - 5.56x45mm. This is the full automatic version of the Mini 14 with a distinctive Barrel and bayonet lug. Ruger also offers the Mini-14 GB ("Government Barrel" Model) which is a semi automatic only version of the AC556 for Law Enforcement and (some) civilian sales. The Full Auto AC556 has a distinctive Auto Selector Switch on the back of the receiver that the Semi Auto Ruger Mini 14 does not.
DefTech 37mm launcher
Defense Technologies "DefTech" launcher with folding stock - 37mm.
Benelli M1 Super 90
Benelli M1 Super 90 in synthetic straight stock configuration, ghost ring sights - 12 gauge
Benelli M3 Super 90
Benelli M3 Super 90 with top folding stock 12 gauge