The Glock 17 is the sidearm carried by the majority of the detectives in the Special Intelligence Unit of the Chicago PD including Antonio Dawson (Jon Seda), Detective Jay Halstead (Jesse Lee Soffer), and Alvin Olinsky (Elias Koteas). The Glock is also carried by the majority of the patrol officers on the show, including Officer Adam Ruzek (Patrick John Flueger) and Officer Kim Burgess (Marina Squerciati).
The hospital bomber uses a nickel Sig Sauer P226 during the rooftop shootout in "8:30 PM" (S1E12), a crossover episode with a Season 2 episode of Chicago Fire.
M4A1-type rifles are used by all the Detectives on raids, usually used by Detective Alvin Olinsky (Elias Koteas) and Detective Jay Halstead (Jesse Lee Soffer). Some of these have barrels different from the typical M4.
Error creating thumbnail: File missingColt M4A1 Carbine with M68 Aimpoint reflex optic, Knight's Armament RAS railed handguard and vertical forward grip - 5.56x45mmError creating thumbnail: File missingDetective Jay Halstead (Jesse Lee Soffer) covers a bus with the M4 while the detectives figure out how to take down the suspect and rescue the hostage in "Wrong Side of the Bars" (S1E02).Error creating thumbnail: File missingJay and Antonio along with some of the other detectives are armed with M4 rifles while clearing a warehouse in "Thirty Balloons" (S1E05).Error creating thumbnail: File missingDetective Alvin Olinsky (Elias Koteas) positions himself on a double decker bus with the M4-type rifle in "Conventions" (S1E06).
Heckler & Koch G36C
A Heckler & Koch G36C is seen being used to shoot at Officer Ruzek and the other detectives in S01E15.
A Remington 870 shotgun fitted with a pistol grip, breaching muzzle, and saddle shell holder is used by Detective Sumners to breach locked doors in "At Least It's Justice" (S1E10).