The following weapons in this film are:
M1911A1
Used by Mason Storm (Steven Seagal).
Mason Storm checks the chamber of his M1911A1 just after he got it back from his friend after years.
M16A1
Colt XM177
Det. Sgt. Goodhart (Dean Norris), Jack Axel (Charles Boswell)
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