Several LAPD officers and detectives carry the Beretta 92FS as their sidearm, including Officer Sammy Bryant (Shawn Hatosy), Officer Bill "Dewey" Dudek (C. Thomas Howell), and Officer Ferguson (Lou Diamond Phillips). This weapon is on the LAPD approved carry list.
Smith & Wesson 5906
Officer John Cooper (Michael Cudlitz) continues to carry the Smith & Wesson 5906 (as evidenced by its double stack frame) as his duty sidearm. This weapon is on the LAPD approved carry list.
Glock 22
Many officers in the series carry as their sidearm the .40 caliber Glock 22 (which is the standard issue handgun for the LAPD). Officer Ben Sherman (Ben McKenzie) continues to carry the Glock 22 as his sidearm. Officer Jessica Tang (Lucy Liu) mentions that she carries the "Glock .40" as her sidearm and draws it in "Wednesday" (S4E01).
Smith & Wesson 3913
In "Wednesday" (S4E01), Officer Ben Sherman appears to carry a Smith & Wesson 3913 as his off duty weapon. He can be seen taking it out of his locker stowed in an IWB thumb break holster. He then fires it later in the episode.
Unknown Handguns
A stainless handgun is seen next to a slain gang member in "Wednesday" (S4E01). Also in the episode, Officer Sherman enters a backyard during a footchase,and several partygoers are seen with various handguns including a revolver and a stainless automatic.
Shotguns
Remington 870 Police Riot Magnum
The Remington 870 Police Riot Magnum is the standard shotgun used by the LAPD in the series. They are often seen in the shotgun racks of the police cars. In Season 4's premiere "Wednesday" (S4E01) Officer Ben Sherman is seen carrying the standard and Officer Sammy Bryant is seen with the "less-lethal" model loaded with beanbag rounds.
Remington 870 Field Shotgun
In Season 4's premiere "Wednesday" (S4E01), a gunman is seen entering the station armed with a Remington 870 Wingmaster Shotgun fitted with an extended mag tube.
Rifles
M1 Carbine
An M1 Carbine is held by an elderly woman in "Underwater" (S4E02).
M4A1 Carbine
An LAPD officer armed with an M4A1 Carbine fitted with an EOTech sight is seen entering after the shootout in the police station in Season 4's premiere "Wednesday" (S4E01).