Garry (Donald Moffat) carries a Colt Trooper Mk III in a holster on his duty belt. Midway through the film MacReady (Kurt Russell) gets possession of Garry's revolver and carries it with him from then on.
Rifles
Heckler & Koch HK93A2
A Heckler & Koch HK93A2 semi-auto rifle with a scope and a 40 round magazine is used at the beginning of the film by the Norwegian with Rifle (Kurt Russell's brother-in-law at the time of filming Larry Franco) to try and kill the infected dog while flying in the helicopter. After the helicopter lands, the passenger hands it to the pilot (Norbert Weisser), who pursues the dog on foot. This scene has in part been reproduced for the prequel, and the passenger renamed Lars. Interestingly, any viewers who speak Norwegian would have the early reveal of the movie ruined in this very first scene, as the armed man explains the nature of the threat.
While Norway has never officially used the HK33 or HK93 in any role, most of the Norwegian defence force used a Norwegian clone of the G3 on license, called the AG3, as the primary issue rifle from 1962 to 2005. The use of the HK93 could therefore be a homage to the AG3, or possibly be used simply because a G3, AG3 or HK91 was not available to the film armorer.
Shotguns
Ithaca 37 shotgun
MacReady (Kurt Russell) carries a Ithaca 37 shotgun several times in the film. At one point Windows (Thomas G. Waites) manages to grab one before he is subdued by the others.
Other
M2A1-7 Flamethrower
This flamethrower is used by several members of the team throughout the movie. Palmer uses a different flamethrower, apparently a propane powered model sold commercially, used for burning weeds, and removing ice from planes and other equipment; the flame on the propane model is very short, at most usually 7 feet. Even so, many scenes in the film use genuine, military-spec liquid-fueled flamethrowers, something of a rarity in movies.