Eric Delko Adam Rodriguez uses a SIG-Sauer P226 Elite as his sidearm during season 9. The gun is identifiable as the Elite model because of its beaver-tail.
In "Reality Kills" (S09E06), an activist is seen with a Walther P99QA. Delko initially things the gun is real but later discovers that it is a pellet gun.
Unknown 1911
In "Blood Sugar" (S09E09), Luis Avilla (Ramón Franco) is seen with an unknown 1911 when confronting the man who had his son deported.
Revolvers
Assault Rifles
Colt M4A1
In "Reality Kills" (S09E06), an MDPD officer is seen armed with a Colt M4A1. Horatio later takes the gun from him and aims it at a suspect.
In "Happy Birthday" (S09E08), MDPD SWAT officers are seein with Colt M4A1s during a raid on a chop shop.
Rifles
Heckler & Koch SR9
In "On the Hook" (S09E07), Dario Aguilar (Joseph Julian Soria) uses a Heckler & Koch SR9 that is chambered for 7.62 but fires a 5.56 round with a Sabot. As Calleigh explains, this allows a smaller caliber bullet to be fired from a higher caliber gun with now groves being left on the bullet.
Ruger Mini-14
In "Fallen" (S09E01), a Ruger Mini-14 is seen pointed at Melissa Walls when the CSIs come to ask her some questions. As it turns out, Melissa set the trap her self to make herself look like a victim.
Shotguns
Unknown Over-Under Shotgun
In "On the Hook" (S09E07), Charles Hayward is seen with an over-under shotgun shooting clays when the cops come to question him.