In the pilot episode (S01E01) Jack Carted (Colin Ferguson) carries a Glock 17 whilst he is still acting as a U.S. Marshall. GD security carries the Glock 17 as well
In "Dr. Nobel" (S1E6) Deputy Jo Lupo (Erica Cerra) is seen carrying Colt Officer's Enhanced Mark IV with pearl grips strapped to her leg. Dr. Beverly Barlowe is seen with a similar gun in a later episode.
Deputy Jo Lupo (Erica Cerra) uses a highly modified Smith & Wesson Model 610 throughout the series. This is the same gun that first appeared in Blade: Trinity where it was known as the "Beef Eater".
After time-travel shenanigans in the the Season 4 premire lead to an alternate timeline, Jo switches to a Walther PPK/S in her new role as GD's Head of Security.
Cusatomized Heckler & Koch USP Matches can be seen throughout the series. They are the custom pistols originally created for Blade II (subsequently also appearing in Blade: Trinity and Blade: The Series). During the episode "Your Face or Mine", two USP Matches are seen behind Fargo while he and Jo (Erica Cerra) are at a shooting range.
Calico M955A (mocked up as M1-L1 Triple-Pulse Rifle)
A heavily modified Calico M955A can be seen in the pilot episode (S01E01) by Deputy Lupo (Erica Cerra), where it is used as the "key" to open a locked door. Practically unrecognizable as a Calico (the only original feature visible is the trigger guard) the weapon can however by identified as the fictional "M1-L1 Triple-Pulse Rifle" which first appeared in Deep Rising. The weapon has an additional cosmetic shell fitted over some portions of the weapon, but still visible from the original Deep Rising prop is the shape of the butt, the five fake muzzles around a central real barrel and the ribbed barrel jacket.
Error creating thumbnail: File missingCalico M955A Submachine gun - 9x19mmError creating thumbnail: File missingFor reference, the M1-L1 Triple-Pulse Rifle as it appears in Deep RisingError creating thumbnail: File missingThe modified Calico is visible in the Sheriff Department's armory. Note the opening in the bottom of the cosmetic silver shell of this weapon, which is necessary due to the base weapon ejecting spent cases downwards.Error creating thumbnail: File missingJo returns with her "key" to the locked door.Error creating thumbnail: File missingA closer shot of the front end of the weapon, showing the fluted barrel shroud and the bracket at the rear of it which match the Deep Rising weapon.Error creating thumbnail: File missingJo unlocking the door. Although it is not clear in this screenshot, the muzzle flash emminated from what appears to be the centre axis for the rotating barrels but what is in actuality the barrel of the Calico.Error creating thumbnail: File missingJack stops Jo from attempting to turn off the time-warping machine by shooting its nuclear fuelled power supply.
Heckler & Koch MP7
Global dynamics security teamd as well as US soldiers are seen carrying MP7s at various points, fitted with Elcan scopes.
Jim Taggert (Matt Frewer) uses a mocked up P90 as a laser weapon in "Phoenix Rising" (S2E1) and again in "A Night at Global Dynamics" (S2E13). A different mockup is used by Jo and various GD security personel as an anti-robot weapon.
Soldiers escorting a nuclear device in "Try, Try, Again" (S2E2) are armed with M4A1 carbines fitted with Aimpoint sights, foregrips, and weapons lights.
A Heckler & Koch G36K with an AG36 grenade launcher is first seen in an armoury in "Before I Forget" (S01E3). Fargo carries a similar weapon in "Alienated" (S1E4)
In "Alienated" (S1E4), Alison Blake carries an L85 of unknown model fitted with a G36's ZF 3x4° dual optical sight and a mocked-up front end as a PEP, "Pulse Energy Projectile Rifle", a less-lethal crowd-control or anti-robotics weapon. Sheriff Carter carries the weapon in "Primal" (S1E9).
American soliders at Camp Eureka carry the M1 Garand when the cast time-travels back to 1947 in "Founder's Day" (S4E1) and "I'll Be Seeing You" (S4E9).
A GD guard is seen manning an Browning M2 Heavy Barrel outside the Artifact chamber and in Level 5. Several other M2s are seen at Camp Eureka in the time-travel episodes, as well as on P-38 Lightning fighters.