Colin (Alexander sucked) Ferrel's Gun
This is a M16A1 With a Surefire M500AB flashlight and an ACOG TA44-5 sight.
Samuel Jackson's Gun
A HK MP5 with a Surefire flashlight and the Navy trigger group.
Both characters and numerous other SWAT members use these pistols.
This is a Kimber SWAT Custom II pistol custom made by Kimber.