In the series premiere "First Responders" (S1E01), Command Sergeant Major Jonas Blane (Dennis Haysbert) carries a custom M1911 handgun of unknown make (it appears, based on the lettering on the slide, that a Colt Government Model may have been used as the base gun, however this is not confirmed). The pistol lacks the front cocking serrations frequently seen on Kimber models (which Jonas carries throughout the rest of the series), but is outfitted with adjustable sights, a combat hammer, a combat trigger, an ambidextrous thumb safety, a beavertail grip safety, a full length guide rod, an extended slide release, Pachmayr grips, and an extended magwell. This weapon is never seen after the pilot episode, which may have been deliberate, as the pistol would likely have been confiscated by base security after the shooting incident at the end of the episode. However, the more likely explanation is that the prop guns were simply unavailable to the filmmakers when shooting subsequent episodes.
Kimber Custom TLE II
The Kimber Custom TLE II is the sidearm of choice for Command Sgt. Major Jonas Blane (Dennis Haysbert) throughout Seasons 1-3 (though he occasionally switches to a Kimber Warrior). Sgt. Hector Williams (Demore Barnes) carries one at the beginning of Season 1 before switching to a P226.
Colt M1911A1
The M1911A1 is a frequent weapon seen in the series. Master Sgt. Mack Gerhardt (Max Martini) carries one as his sidearm. In "Eating the Young", the arms dealer Adolpho (Luis Antonio Ramos) pulls a gold-plated M1911A1 on Bob.
Colt Compact M1991A1
In "Unannounced" (S1E10), a Colt Compact M1991A1 is seen in the purse of Kim Brown (Audrey Marie Anderson). When Kim is threatened by a man at the radio station, Rory is seen pulling the Colt on the man.
Colt Mustang
Hector is briefly seen using a stainless Colt Mustang during the final gunfight in Season 1's "The Wall".
SIG-Sauer P226
The SIG-Sauer P226 is the sidearm of Sgt. Charles Grey (Michael Irby) and Sgt. Hector Williams (Demore Barnes) throughout the series. Master Sgt. Mack Gerhardt (Max Martini) uses a P226 throughout Season 1 before switching to his M1911A1.
SIG-Sauer P230
The SIG-Sauer P230 was used in Season 1's "True Believers" and also carried by Colonel Ryan in Season 1's "The Wall".
Glock 23
In Season 1's "Non-Permissive Environment" (S1E5), a Glock 23 is the handgun Jonas Blane's daughter Betsy (Angel M. Wainwright) finds in a drawer at the Blane's home. She later fires it on the range.
Glock 17
The Glock 17 is one of the weapons prominently featured throughout the series. Bob Brown (Scott Foley) used a Glock 17 in Season 1 before he switched over to the P226.
Beretta 92FS
The Beretta 92FS has been seen in the hands of SWAT members, Unit members, and US military CID agents. In the Season 1's "Dedication", Jonas carries a Beretta holstered on his vest. Sam McBride (Wes Chatham) takes a 92FS from a police officer in Season 4's "Whiplash". In the series premier "First Responders" Jonas uses an ISS Beretta Non Gun to kill Grey's mule.
Beretta "Non Gun"
In "First Responders" (S1E01), the pistol used by Jonas to dispatch a mule appears to be a Beretta Non Gun.
Beretta 950 Jetfire
In Season 1's "True Believers", Mack hides a Beretta 950 Jetfire in his pants that he uses on The Major.
Walther P5
A Walther P5 with a stainless steel finish was used by the African soldier in Season 1's "Stress".
Walther TPH
Mack uses a Walther TPH in the Season 1 finale "The Wall" when the terrorists attack the Unit and their wives at Ryan's private reception.
High Standard Derringer
In the Season 1 finale "The Wall", Jonas carries a nickel plated High Standard Derringer and uses it on men who attack the Unit at Ryan's private reception. Jonas' Derringer has barrels that tip down and when Jonas places it in his waistband it appears to have a double action trigger.
Norinco Model 54
A Norinco Model 54 was used by the rebel leader in Season 1's "200th Hour." Model 54s were also seen used by Chinese officers in Season 4. A Norinco is found in a bag of an escaped convict who used to be a Unit operator in Season 2's "Extreme Rendition".
High Standard Sharpshooter M
Bob Brown (Scott Foley) was presented with .22 cal High Standard Sharpshooter M with wooden grips when he and Jonas visit a former Unit member in the Season 1 premiere "First Responders" (S1E01). In "Exposure" (S1E11), the pistol seen (very briefly) used by Ryan in a flashback. Despite being a suppressed weapon, the sound effect used is that of an unsuppressed gunshot.
Browning Hi-Power
The Browning Hi-Power is used by several characters throughout the series.
Seecamp LWS-32
In Season 1's "Non-Permissive Environment", Bob plants a Seecamp LWS on a civilian in order to escape the police.
Revolvers
Colt New Service
A Colt New Service is used by a Brazilian soldier to threaten a mother and her child in Season 1's "Eating the Young."
In "200th Hour" (S1E03), Rudy Hartano (Tzi Ma) pulls a Smith & Wesson Model 36 on Jonas when he fears he's been double-crossed.
Submachine Guns
Heckler & Koch MP5A2
Both Alpha and Bravo teams of the Unit are seen using Heckler & Koch MP5A2 submachine guns in "200th Hour" (S1E03). Also prominently used by the Unit in "True Believers" (S1E04).
Jonas, Mack and Hector are all seen using Heckler & Koch MP5K submachine guns in the series. Jonas and Mack were seen using the newer Navy trigger group variant, while Hector was seen using one with the old "SEF" trigger. Bob also uses one in Guyana to cover Jonas's escape.
A Mini-Uzi is used by a hijacker on the plane in Season 1's premiere "First Responders".
Cobray M11/9
Dragovich (Yasen Peyankov) uses a Cobray M11 in his attack on the Unit during the Col. Ryan's reception dinner in the Season 1 finale "The Wall" (S1E13).
Škorpion vz. 61
A Škorpion vz. 61 was seen in the hands of an Iranian embassy guard in the Season 1 episode "Security."
AP-9
One of Dragovich's men uses an AP-9 in the attack on the Unit during the reception dinner in Season 1's "The Wall".
MAT-49
At least one of the Indonesian rebels carries a MAT-49 in Season 1's "200th Hour".
Battle Rifles/Carbines
Colt M4A1 Carbine
M4A1 Carbines are used by all members of the Unit, often with a 40mm M203 Grenade Launcher, and with an optical sight (normally the Trijicon ACOG, Aimpoint CompM2 and/or EOTech 552 Holographic sight). Sometimes they switch with HK 416s.
Heckler & Koch G36C
The Heckler & Koch G36C is carried by Sgt. Grey in the Season 1 finale "The Wall" (S1E13).
SIG SG 552
Sgt. Grey carries a SIG SG 552 in "Stress" (S1E02). Jonas, Bob, and Hector all carry these rifles in the Season 1 finale "The Wall" (S1E13). (Jonas's is briefly seen with a suppressor).
FN FAL
Several FN FAL Variants are seen in the hands of Jonas and Hector in "Stress" (S1E02). Jonas uses one with iron sights while Hector's is fitted with a scope. These were the full length FALs and one might of had a wooden stock. It was hard to tell.
SA Vz.58
In Season 2's "Bait", the Georgian rebels who hold Jonas hostage are armed with SA Vz.58 rifles.
AK variants
Variants of the AK are featured throughout the series. All members of the Unit is seen using an AK at least once throughout the series. Most enemies have also used the rifle.
M70B1 and M70B2
AKMSU
The shorty AKMSU carbines (AKM rifles converted with Krinkov parts kits and AKS-74U side-folding stocks) were used in several episodes.
Seen throughout the series, but featured prominently in Season 2's "Johnny B. Good", where each member of the Unit carries an AKM rifle fitted with suppressor and Surefire light on their mission to Iran.
Special
FN F2000 Tactical
Jonas can be seen using an FN F2000 Tactical fitted with a scope in Season 2's "Extreme Rendition" (S2E2).
FAMAS
The FAMAS rifle is seen in the hands of French Soldiers in Season 1's finale. Also seen in the hands of soldiers in South East Asia.
Ruger Mini-14
A Ruger Mini-14 is seen resting on a tree by one of the terrorist lookouts that Bob takes out in Season 1's "First Responders". Also seen used by a man in episode 4 of season 1.
Heckler & Koch G3
Heckler & Koch G3 rifles are used by rebel forces aiding the Unit in Season 4's "Flesh & Blood" (S4E17).
Heckler & Koch HK91
A Heckler & Koch HK91 is used by a boy soldier used by an arms dealer to guard his home in Season 1's "Eating the Young" (S1E9). Some are obviously non-firing replicas, likely done for the safety of the child actors.
Galil ARM
One of the guards fires at the Unit with a Galil ARM in Season 4's "The Conduit".
Shotguns
Mossberg 500 Cruiser
A Mossberg 500 Cruiser is seen among the weapons packed on a mule in Season 1's premiere "First Responders" (S1E01).
Benelli M3 Super 90
The Benelli M3 Super 90 shotgun are the main weapons of Alpha Team members Charles Grey (Michael Irby) and Hector Williams (Demore Barnes) in Season 1's premiere "First Responders" (S1E01)". Also seen in the hands of the US Rangers that accompany them in the assault of the plane.
Stevens 512 Gold Wing O/U Shotgun
Jonas shoots skeet with a Stevens 512 Gold Wing O/U Shotgun chambered in 12 gauge owned by the Oil Minister. (It seems that even high-ranking government officials cheap out on shotgun choice.)
Remington 870 Wingmaster
Mack used a vintage Remington 870 shotgun while posing as a bird hunter in "True Believers" (S1E04).
Machine Guns
FN MAG mocked up as M240
FN MAG machine guns mocked up to resemble the M240 are seen in use by French UN forces in the Season 1 finale "The Wall". They are recognizable as the M240G due to lack of heat shield but most likely, these are actually original FN MAGs mocked up to look like the M240G.
PKM Machine Gun
A PKM Machine Gun was used by African forces in "Stress" (S1E02).
DShKM Heavy Machine Gun (Browning M2 mockup)
A Browning M2 mocked up to resemble the DShK heavy machine gun is frequently used in the series. It's fired by Taliban warriors in Season 1's "Dedication" (S1E7), set up by Syrian forces in Season 4's "Into Hell, Part II" and fired by Mack in Season 4's "Switchblade".
Sniper Rifles
Mark 12 Mod 0 SPR
A Mark 12 SPR is used by Jonas in "Eating the Young" (S1E09).
Armalite AR-10
In Season 1's "Dedication", Bob uses an Armalite AR-10 was dressed up as a sniper rifle, most likely as a placeholder for the Knight's Armament SR-25. It is not a SR-25 due to the the fencing around the magazine release, the SR-25 lacking this feature. Bob fires it on full auto while in the chopper, despite the fact that its trigger group clearly lacks an "Auto" option, but this was most likely added in post-production editing because no casings are ejected and the dust cover remains in place.
Heckler & Koch PSG1
In "Stress" (S1E02), Mack used a PSG1 with great effect. His rifle had a 20 round magazine in it.
Remington 700 AICS
A sniper rifle frequently used by The Unit is a Remington 700 AICS. Bob is seen firing one in Season 1's "Non-permissive Environment".
Rifles/Carbines
Lee-Enfield No.1 Mk.III
A Taliban warrior uses a Lee-Enfield No.1 Mk.III to wound a chopper pilot in Season 1's "Dedication" (S1E07).
Special
SKS rifle
The SKS rifle was used by terrorists in Season 2's "In Loco Parentis" (S2E20). The rifle was also seen in Season 1's "200th Hour" (S1E3).
Special
M1 Carbine
In "200th Hour" (S1E03), Indonesian rebels are seen carrying M1 Carbine rifles.
Hi-Point Carbine
One of the terrorists who attacks the wedding reception in Season 1's "The Wall" uses a Hi-Point Carbine. Despite being a semi auto weapon in reality, it is depicted firing full auto. Obviously that terrorist had converted that weapon into full auto.
Launchers
FIM-92A Stinger
Bob Brown (Scott Foley) is seen taking out a helicopter with a FIM-92A Stinger in the Season 1's "Eating The Young."
Chinese Type 69 RPG
Several Type 69 RPG's are seen being used throughout the series. In Season 1's finale "The Wall" (S1E13), Dragovich's men fire one at oncoming French forces. The example seen here us the Chinese Type 69 launcher (the Chinese version of the SovietRPG-7). The biggest difference is that the Chinese RPG had only one pistol grip. The second hand has to grasp a carry handle on top of the launcher. The Type 69s in the series have PGO-7 scopes mounted on the launcher.
Other Weapons
M67 "Baseball" Grenade
The M67 "Baseball" Grenade is used throughout the series. Bob uses one to spike a mortar in "Dedication" (S1E07).