The Glock 17 is carried by most of the CSIs throughout season 8. both Detective Mac Taylor (Gary Sinise) and Sergent Danny Messer (Carmine Giovinazzo) use Glock 17s. Also, any NYPD officer (unless otherwise indicated on this page) seen with a pistol is also using a Glock 17.
Glock 26
The Glock 26 is the sidearm of both Detective Lindsay Monroe Messer (Anna Belknap) and CSI Jo Danville (Sela Ward).
In "Means to an End" (S08E09), Jo's Glock is taken from her when she is attacked by John Curtis (Jason Wiles). He mocks her by pushing each bullet out of the magazine but makes the classic mistake of forgetting the one in the chamber.
Makarov PM
In "Crossroads" (S08E08), Tommy Hill (James Preston) as the hitman on a bicycle uses a Makarov PM to assasinate a Judge. It is identified by the CSIs as a "Baikal IJ 70" which is the name under which the Makarov was sold in the US during the 1990s.
In "Indelible" (S08E01), a bar robber is seen with an unknown pistol. Possibly a Walther PPK?
Unknown #2
In "Officer Involved" (S08E04), Officer Lauren Cooper (Jeananne Goossen) pulls Danny's backup weapon out of his ankle holster and fires it at an armed man.
In "Indelible" (S08E01), a bar robber uses an unknown revolver. Possibly a Taurus Model 85?
Unknown #2
In "Officer Involved" (S08E04), Travis Moss (Jeff Leaf) pulls an unknown S&W revolver. This appears to be the same revolver as the one above.
Unknown #3
In "Officer Involved" (S08E04), Mac uses an unknown revolver when doing a test in the lab.
Submachine Guns
Shotguns
Unknown Pump-Action
In "Cavallino Rampante" (S08E03), Lindsay Monroe Messer (Anna Belknap) uses an unknown pump action shotgun fitted with a tactical light.
Assault Rifles
Colt Model 933
Throughout season 8, ESU members are often seen using the Colt Model 933.
In "Cavallino Rampante" (S08E03), when arresting Nathan Purdue AKA Dominic Yanos (Time Guinee), ESU members are seen with their Colt Model 933s.
Sniper Rifles
Gun Collections
Gun Lab
The gun lab is seen in multiple different episodes when the CSIs are test firing guns.