In the pilot episode (S01E01), Jack Carted (Colin Ferguson) carries a Glock 17 whilst he is still acting as a U.S. Marshal. GD security carries the Glock 17 as well
Colt M1911A1
Soldeirs are seen with the Colt M1911A1 after the cast time-travels back to 1947 in "Founder's Day" (S4E1).
Colt Officer's Enhanced Mark IV
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) can be seen cleaning a number of pistols in the pilot (S01E01) including a Beretta 92FS Inox.
Smith & Wesson Model 610
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".
Walther PPK/S
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.
Heckler & Koch USP Match
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.
Heckler & Koch Mark 23
A Heckler & Koch Mark 23 fitted with a suppressor and laser aiming module can be seen on a wall in "Before I Forget" (S01E03).
There is a Mossberg 500 with wood furniture sitting in a gun rack in the Sheriff's office.
Remington 870
There is a Remington 870 sitting in the gun case in the Sheriff's office.
Sub-Machine Guns
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.
Heckler & Koch MP7
Global Dynamics security teams as well as US soldiers are seen carrying MP7s fitted with Elcan scopes.
FN P90
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.
Assault Rifles
M16A2
M16A2s are used by the U.S. marines that respond to the crisis in the pilot (S01E01).
M4A1 Carbine
Soldiers escorting a nuclear device in "Try, Try, Again" (S2E2) are armed with M4A1 carbines fitted with Aimpoint sights, foregrips, and weapons lights.
Heckler & Koch G36K w/ AG36
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)
Heckler & Koch G36C
A Global Dynamics tactical team comander carries a G36C with an export sight in "Alienated".
L85
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).
Rifles
Remington Model 700 (Takedown rifle)
A taken down Remington Model 700 in a Choate Super Sniper Stock can bes seen in the Sheriff Department armory in the pilot (S01E01).
Winchester 1894
There is a Winchester 1894 sitting in the gun display case in the Sheriff's office.
Remington 700
There is a Remington 700 sitting in the gun display case in the Sheriff's office.
M1 Garand
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).
Machine Guns
M60E3
An M60E3 is used to test a personnel shielding system in "Before I Forget" (S01E03).
M249 Paratrooper SAW
In "Alienated" (S1E4), Vincent (Chris Gauthier) carries an M249 Paratooper SAW with a suppressor, ELCAN sight, and 100-round cloth ammo bag.
Browning M2 Heavy Barrel
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.
Other
Tranquillizer Rifle
Dr. Jim Taggart (Matt Frewer) uses an unidentified tranquillizer rifle in the pilot (S01E01) and again in "Alienated"(S1E3).
"Sun Dog" Electronic Pistol
A number of the "Sun Dog" electronic pistols from Blade: Trinity can be seen in various gun racks throughout the series.
Plasma rifle
What appears to be some sort of plamsa rifle is fired by a GD security officer in "Invincible" (S1E5)
Custom Flamethrower
Sheriff Carter (Colin Ferguson) uses a flamethrower in "Purple Haze" (S1E9)