Lt. Carter Shaw (Dylan McDermott) switches his SIG-Sauer P228 to a customized Colt MK IV Series 80 halfway into the first series. The same pistol is also used by Jimmy (Cole Hauser) in the series Chase and also by Detective Ludlow (Keanu Reeves) in the film Street Kings. Before the particular gun becomes Shaw's sidearm in the series, an unknown thug working for Howard (Al Sapienza) can briefly be seen with it, before being gunned down by Curtis in episode "Purity" (S01E03).
Kahr K9
After the pilot, Jaimie Allen (Nicki Aycox) starts carrying a Kahr K9 pistol as her sidearm. She carries it throughout the first series.
Ty Curtis (Omari Hardwick) keeps a nickel plated Colt Government Model pistol in a safe box, alongside a Beretta 92FS. He takes it out and uses it in the pilot episode after Lt. Shaw (Dylan McDermott) sends him back undercover.
Jack Walsh (Clayne Crawford) also keeps an M1911A1 as his sidearm in episode "K-Town" (S01E04). He is only briefly seen firing it at Curtis, but he is quickly disarmed by Dean Bendis. His 1911 seems to be fitted with either Novak or Bomar sights. Lt. Jay Frye (Michael Biehn) also uses a customized M1911A1 as his sidearm in the episode "O.I.S" (S01E07). His 1911 is fitted with Novak sights. A thug working for a smuggler named Frank (Jamie McShane), also briefly handles a regular M1911A1 in the beginning of episode "Betsy" (S01E09). One is also seen in the same episode amidst the guns that Shaw is using as bait.
Beretta 92FS
Ty Curtis has a Beretta 92FS in a safe box alongside his Colt Government Model in the pilot episode. The Beretta 92FS is also used by a guard and one of Warren Volk's men in the bank during the pilot episode. Dean Bendis (Logan Marshall-Green) also has a Beretta 92FS in a locked box along with his drugs and cash hidden under his floor boards. A Korean gangster, Kang (Brian Tee) also uses a Beretta 92FS in episode "K-Town" (S01E04). A Korean thug is also seen firing a 92FS in the same episode. A couple of thugs working for Dante Rollings (Gbenga Akinnagbe) are also seen with Berettas in episode "August" (S01E05). Officer Noyce (John T. Woods) and Officer Kim (Yun Choi) of Lt. Frye's (Michael Biehn) rogue task force also carry the Beretta 92FS as their sidearms in episode "O.I.S" (S01E07). A Beretta is also seen lying on a table in a drub lab in the same aforementioned episode. In episode Venice Kings (S01E08), Pike (Matt Bushell) and leader of the Venice Kings Mike O'Neill (Shawn Doyle) both carry Beretta 92FSs. In Betsy (S01E09), Frank (Jamie McShane) also carries a Beretta. In the same episode, a Beretta can also be seen in the midst of the guns that Shaw is using as bait. In episode "Urban Garden" (S02E01), a thug working for Serbian gangster Victor (Rhys Coiro) tries to pull a Beretta 92FS on Lt. Carter Shaw, but is quickly gunned down by Dean Bendis.
Beretta 92FS Inox
A member of the Korean mafia uses a Beretta 92FS Inox as his sidearm in the episode "K-Town" (S01E04). He is seen assembling it in the beginning, in a race against Dean Bendis (Logan Marshall-Green). He uses it later to try to shoot Dean.
Robert Franzine (James Russo) carries as his sidearm in the pilot episode a Ruger KP90. He uses it most notably in the bank "robbery" during the pilot episode.
Ruger KP89
Johnny Moosa (Gonzalo Menendez) carries a Ruger KP89 as his sidearm in the second episode. He uses it to threaten Ty.
Glock 17
Jaimie Allen (Nicki Aycox) carries a two-tone Glock 17 as her sidearm only in the pilot, and can be seen using it in the gun range, and also during the climax shootout of the pilot. Her Glock switches into a Kahr 9 after the pilot, and remains her sidearm for the rest of the series.
In the pilot episode, some of Warren Volk's and Robert Franzine's men carry regular Glock 17s. In episode "Ice" (S01E06) Tommy Franco (Jonathan LaPaglia) keeps a Glock 17 in his safe. Also one of Dan Kemp's (Michael Bowen) heist crew keeps a Glock 17 as his sidearm in the same episode.
Glock 19
In episode "Ice" (S01E06) Joey Becker (Kwame Patterson) pulls out a Glock 19 on Dean Bendis (Logan Marshall-Green).
Officer Chavez (Jon Huertas) of Lt. Frye's (Michael Biehn) task force, has a Glock 19 as his sidearm in episode "O.I.S" (S01E07). In the season finale of the first season (episode "A Shot in the Dark"), corrupt undercover DEA agent Steve Fuller (Victor Browne) uses a Glock 19 to fire at Dean Bendis during the beginning deal. FBI Special Agent Alex Rice (Tricia Helfer) carries the Glock 19 as her sidearm throughout the second series. Phil Doyle (Jack Stehlin), a hitman working for the Serbian gangster Victor (Rhys Coiro) also uses a Glock 19 in episode "Urban Garden" (S02E01). He wields it both suppressed and unsuppressed.
Glock 21
In episode "O.I.S" (S01E07) Ty Curtis exceptionally has a Glock 21 as his sidearm, as he is trying to infiltrate a task force, led by Lt. Jay Frye (Michael Biehn). This involves him going back to work as a plain clothes officer. Apparently the Glock 21 was Curtis' duty weapon.
Glock 26
A Korean gangster, Kang (Brian Tee) is briefly seen loading up a Glock 26 in episode "K-Town" (S01E04).
Jaimie Allen (Nicki Aycox) briefly wields a Heckler & Koch USP Compact during a setup drug deal in episode "Guns, Strippers and Wives" (S01E02). A thug working for Howard (Al Sapienza) pulls a Heckler & Koch USP Compact when Howard orders him to kill Reuben Pike in episode "Purity" (S01E03). He is gunned down before he gets a chance, though.
Heckler & Koch USP
Ty Curtis (Omari Hardwick) uses a Heckler & Koch USP to arrest Johnny Moosa when they are in Ty's house in the second episode ("Guns, Strippers and Wives"). Dean Bendis (Logan Marshall-Green) starts carrying the USP as his sidearm beginning in S01E08, and uses it for the remainder of the show. A USP can also be seen in the midst of the guns Shaw is using as bait in episode "Betsy (S01E09).
Smith & Wesson 4506
In episode 2 ("Guns, Strippers and Wives"), Jimmy Boyd (Gregg Henry) is briefly seen putting a Smith & Wesson 4506 to the head of Ty. The particular 4506 used in this episode is the exact same one used by Keanu Reeves in the 2008 film Street Kings (same armorer, same prop). A pair of snake eyes dice with "Vice Special" is printed on the right side of the slide between the ejection port and the muzzle. The same prop is also re-used in episode "August" (S01E05), as Dante Rollings' (Gbenga Akennagbe) sidearm. Shaw eventually takes the gun away from Dante, and points it at him.
Smith & Wesson 5904
A Korean gangster puts a Smith & Wesson 5904 on Ty's throat in episode "K-Town" (S01E04), when Dean Bendis is accused of cheating by one of the Koreans.
Ty Curtis pulls a Rohrbaugh R9 in episode "Purity" (S01E03). He uses it to dispatch an enemy.
Revolvers
Smith & Wesson 640 Centennial
A drug buyer tries to pull a Smith & Wesson Model 640 Centennial on Shaw in the second episode, when they are trying to come up with a 100 grand to save Ty.
Smith & Wesson Model 36
A Smith & Wesson Model 36 snub-nose revolver can be seen Reuben Pike's trunk in the third episode, Purity. Bendis and Allen plant this gun, and some coke, in Pike's trunk to make sure he will be co-operative.
Colt Detective Special
In episode "Ice" (S01E06), Dan Kemp (Michael Bowen) gives one his heist crew a nickel plated Colt Detective Special, saying that if he wants out, he has to play Russian roulette.
Smith & Wesson 66 "Non Gun"
Dean Bendis (Logan Marshall-Green) uses a Non Gun Revolver in episode "A Shot in the Dark" (S01E10), as he plants two .38 bullets at a crime scene. Non Guns are used when real, blank-firing guns are not necessary.
Unknown snub-nosed revolvers
In the pilot episode, one of Warren Volk's bodyguards has an unknown snub-nosed revolver in an ankle holster. He tries to use it but is gunned down by one of Franzine's crew members. Lt. Frye (Michael Biehn) is also briefly seen planting a snub nose revolver into the hands of a dead drug dealer in episode "O.I.S." (S01E07).
Sub-machine guns
Heckler & Koch MP5A2
In the second episode when Ty is undercover he is trying to buy guns from Johnny Moosa. Among other weapons there are Heckler & Koch MP5A2s. Moosa also tests one of the MP5's, which is fitted with a holographic sight. A thug from Moosa's crew also tries to use an MP5A2 during the trade in episode 2, but Dean intervenes.
Heckler & Koch MP5A3
A couple of SWAT officers load up their Heckler & Koch MP5A3 submachine guns before a raid in episode "Venice Kings" (S01E08).
Machine pistols
Cobray M11/9
In episode "Venice Kings" (S01E08), a Lokes hit team uses a Cobray M11/9 in a drive-by hit attempt on Venice Kings members.
Rifles
Colt M4A1 Carbine
Most of Robert Franzine's (James Russo) men use M4A1 carbines in the pilot episode, including undercover Officer Dean Bendis (Logan Marshall-Green). They most notably use them during the bank job, and the ensuing shootout. A couple of M4A1s are also seen in episode 2, "Guns, Strippers, Wives": First in the container when Ty Curtis (Omari Hardwick) checks Johnny Moosa's merchandise, and later in the back of a van during the trade off.
A flattop M4A1 with a flip-up adjustable rear sight is also seen used by one of Neal's (David Fabrizio) men in episode "O.I.S." (S01E07). Jaimie Allen (Nicki Aycox) also handles a flattop M4A1 in "Betsy", as Shaw and her are preparing a fake smuggling deal.
SVD Dragunov
Amidst the weapons that Carter Shaw (Dylan McDermott) uses to fake a transportation deal in S01E09, is a SVD Dragunov. He briefly handles it, as he shows off the gun.
Several M16A1 rifles fitted with M16A2 handguards can be seen in a container in episode nine ("Betsy"), as Dean Bendis (Logan Marshall-Green) is packing the container.
Shotguns
Remington 870
Lieutenant Carter Shaw (Dylan McDermott) uses a Remington 870 shotgun with synthetic furniture, rear pistol grip and extended barrel in the pilot episode shootout near the end. Pike (Matt Bushell) also uses a one in episode Venice Kings (S01E08). His shotgun is also fitted with a heat shield.
One of Robert Franzine's (James Russo) men is seen loading a Remington 870 when they prepare for the bank job in the pilot episode. Dean Bendis is also seen with one in episode "Ice" (S01E06) as he robs some robbers of their stuff. Officer Kim (Yun Choi) is also briefly seen with one, when Lt. Frye's rogue task force is outside Dean Bendis' apartment in episode "O.I.S." (S01E07).
Lt. Carter Shaw and Dean Bendis also use tactical Remington 870 Police shotguns fitted dedicated Surefire forend weaponlights whenever they need to make a bust. Officer Allen (Nicki Aycox) is also briefly seen loading one of these Remingtons in episode "K-Town" (S01E04). Ty Curtis (Omari Hardwick) also uses one in episode "Urban Garden" (S02E01), while he's standing by as back up with Jaimie Allen for FBI agent Alex Rice (Tricia Helfer). Undercover FBI agent Bill Pierce (Sean Donnellan) also loads and handles a tactical Remington 870 Police in the same episode, during the bust near the end of the episode.
During an attack on the Serbian gangster Victor's (Rhys Coiro) hideout in episode "Urban Garden" (S02E01), Ty Curtis (Omari Harwick) uses a Remington 870 shotgun with an extended magazine tube, a breacher barrel and a rear pistol grip.
When Dean Bendis (Logan Marshall-Green) tries to set up an ecstasy deal while he's undercover in episode "Urban Garden" (S02E01), undercover FBI agent Bill Pierce (Sean Donnellan) pulls a regular Remington 870 shotgun on him.
Benelli M1 Series Super 90
A Benelli M1 Series Super 90 is carried and used by one of Lt. Shaw's acquaintance's Neal's (David Fabrizio) men in the episode "O.I.S." (S01E07) during the raid on the drug lab. It is seen fitted with a Surefire tactical light.
Ithaca 37
In episode "O.I.S." (S01E07) Lt. Shaw's (Dylan McDermott) acquintance, Neal (David Fabrizio) uses an Ithaca 37 shotgun when they destroy a drug dealer's lab together.
Machine guns
Browning M1919
In episode "Betsy" (S01E09), a Browning M1919 machine gun can be seen in the midst of the guns Carter Shaw (Dylan McDermott) is using as bait.
M60
An M60 machine gun can be seen amidst the guns in episode "Betsy" (S01E09), that Carter Shaw is using as bait.