The Glock 17 appears frequently in the series, most often as the sidearm of choice for U.S. Marshal Chris Monsanto (Chris Elliott), his partners Susie (Maria Thayer), Brett (Brett Gelman), and his various deceased ex-partners. Chris appears to have a Glock with a ported barrel. He uses a suppressed Glock 17 in "A Mug of Chili and a Bowl of Death" (S01E12).
A now mentally handicapped Vargas has a nickel SIG-Sauer P226 duct taped to his hand and is forced to shoot at rival Logan by Chris in "Get Worse Soon" (S1E01). Doolan (Peter Woodward) can be seen using one in "The Human Bat" (S01E9).
Beretta 92FS
Logan (V.J. Foster) shoots back with a Beretta 92FS in "Get Worse Soon" (S1E01). An Albanian hitman is seen using a suppressed Beretta 92FS in "Chris, Susie, Brett and Malice" (S01E07).
Beretta 92FS Inox
Joe the Mugger (Matt Lasky) uses a Beretta 92FS Inox to hijack the hot air balloon in "Master of da' Skies" (S01E03).
Susie's stalker Arnold (Josh Fadem) uses a Smith & Wesson Model 629 with a 3" barrel to shoot the Secretary of Transportation and later the Governor. Brett and Chris later take it away from him.
Shotguns
Mossberg 590
Cyrus Barnaby (Donovan Scott) carries a cut down Mossberg 590 with a heat shield in "Me Llamo Justice" (S01E04).
Remington Model 31
A Remington Model 31 with black furniture and a cut down barrel is seen in several episodes.
Submachine Guns
MAC-11
Various thugs carry MAC-11 submachine guns. Brett carries one when he briefly joins Doolan's gang in "The Human Bat" (S01E9).
Assault Rifles
M4A1 Carbine
Various henchmen carry M4A1 carbines fitted with various accessories such as RIS foregrips and M68 Aimpoint & ACOG scopes.
Other
M67 Hand Grenade
The Baron drops M67 hand grenades on the US Marshals' office, goading Chris in "Master of da' Skies" (S01E03).
Wall of Guns
The swingers reveals their arsenal in "Chris, Susie, Brett and Malice" (S01E07).