All of the Vermont State Police troopers, including Rod Farva (Kevin Heffernan), Foster (Paul Soter), Thorn (Jay Chandrasekhar), Rabbit (Eric Stohanske) and Capt. John O'Hagen (Brian Cox) use Glock 17s. The Spurbury Police, including Chief Grady (Daniel von Bargen), Local Officer Smy (Michael Weaver), Local Officer Burton (Dan Fey), Local Officer Rando (James Grace), Ursula (Marisa Coughlan), and later Farva, also use Glock 17s.
Shotguns
Remington 870
Each police force uses a Remington 870 shotgun, seen in the hands of Farva, Ursula, and Mayor Timber (John Bedford Lloyd). Note that the magazine tube on all the 870s in the film are stainless, indicating the same gun was used for all scenes due to budget constraints.
Other
Marksman Repeater BB gun
When Spurbury police captain Grady draws his pistol inside the trailer, it appears to be a Marksman Repeater BB pistol, possibly a Marksman 1020.