The Smith & Wesson Model 66 is used by several LE officers, and is picked up by Jim Halsey (C. Thomas Howell)
Remington 870
The Remington 870 is used by the State police, specifically during the Highway chase.
M16 SP1
A State trooper riding in a Helicopter fires on Jim Halsey during the Highway chase with a M16 SP1. Several of the State troopers escorting John Ryder (Rutger Hauer) are also armed with M16 SP1s..
Custom Smith & Wesson 629
At the end of the movie, Jim Halsey (C. Thomas Howell) grabs a gun from a police officer. It is a 2.5"-barreled, Mag-na-ported S&W N-frame (probably, a Smith & Wesson 629 ). A similar gun can be seen in the movie Extreme Prejudice
Carried by some cops escorting John Ryder to the state prison, later used by John Ryder, and finally used by Jim Halsey (C. Thomas Howell) to kill John Ryder.
Trivia
In addition to scenes shot in the studio, filming locations include Amboy, California, Barstow, California, Death Valley National Park in California, Imperial County, California and Lake Mead in Nevada.