Detective Hieronymus "Harry" Bosch (Titus Welliver) carries a Kimber Custom TLE II as his service weapon. The Kimber is the pistol author Michael Connelly specifies as Bosch's LAPD sidearm in his later novels.
Glock 17
Bosch's partner, Detective Jerry "J. Edgar" Edgar (Jamie Hector) carries what appears to be a Glock 17 as his service weapon. LAPD patrol officers also carry the Glock as their sidearms (the Glock 22 is the official department issue of the LAPD).
Beretta 92FS
The Beretta 92FS, which was previously the department-issued service weapon of the LAPD, is seen carried by some of the veteran detectives in the series, including Det. Moore (Gregory Scott Cummins). The handgun also is seen in the hands of Raynard Waits (Jason Gedrick). Bosch is also seen teaching his daughter how to shoot a Beretta in "Chapter Six: Donkey's Years" (S1E06).
Beretta 92SB
In "Chapter Four: Fugazi" (S1E04), the pistol that Raynard Waits (Jason Gedrick) uses after his escape appears to be a Beretta 92SB. He uses a Beretta 92FS in later episodes.
Colt Mustang
Bosch recovers a Colt Mustang at the scene of what he later determined to be a suicide in the pilot episode "Chapter One: 'Tis the Season" (S1E01).
Colt Model 1908 Vest Pocket
When a plantiff's attorney gives her version of a shooting, Bosch is described as leaving a small pocket pistol as a drop piece at a crime scene. The pistol resembles a Colt Model 1908 Vest Pocket. This was only seen in the original version of the pilot episode.
Shotguns
Mossberg 500
A Mossberg 500 is seen mounted in the trunk of Bosch's police cruiser in "Pilot" (S1E01).
Remington 870
A "less lethal" Remington 870 loaded with beanbag ammo is used by Officer Randell Pierce (DaJuan Johnson) near the end of "Us and Them" (S1E10).