In "The Cost of Living" (S05E05), Diakos (Adoni Maropis) uses what appears to be a Beretta 92FS when he assaults Stella. The gun is refered to as a "high caliber automatic pistol".
In "No Good Deed" (S05E16), a suspect drops a Beretta 92FS when being detained by Mac.
In "Point of No Return" (S05E18), Dr. Marty Pino (Jonah Lotan) uses an unknown pistol that appears to be a nickel-plated Beretta 92SB (due to the rounded trigger guard).
In "Turbulence" (S5E03), Flack finds a Desert Eagle with pearl grips in a hotel room where an Air Marshal was murdered, the suspect apparently used a stuffed animal to suppress the sound of the gunshot.
In "Pay Up" (S5E25), a Desert Eagle is used by a kidnapper to kill Det. Jessica Angell. The kidnapper is seen using it in the climax of the episode, dropping it after being wounded by Flack. Hawkes is also seen holding one while he and Det. Monroe examine the .50AE round discovered at the crime scene.
In "Yahrezit" (S05E22), a Neo-Nazi has several Luger P08 pistols. Another Luger fitted with a bayonet on the barrel is used by an ex-Nazi named Klaus Braun (Ed Asner) to commit a murder. The round doesn't penetrate deeply due to the gunpowder having degraded over the years.
In "Communication Breakdown" (S05E19), what appears to be a Mauser 1910 Pocket Pistol is used by a father to ward off the man sleeping with his daughter. When the gun accidentally discharges it strikes a man on a passing train. The gun is misidentified as a .25 caliber.
In "Turbulence" (S05E03), an air marshal's SIG-Sauer P229 is found by Adam, identified as a "Sig". The SIG is later seen in a flashback when James Turner (Scott Connors) holds the gun on a flight attendant.
In "Yahrezit" (S05E22), a Neo-Nazi is found in poseession of a Walther P38 along with his Lugers. Adam is later seen testing the weapon to match it against the murder weapon.
In "The Past, Present and Murder" (S05E21), a Smith & Wesson Model 65 is found in Dunbrook's (Craig T. Nelson) office. It is identified as a "Smith & Wesson .38 Special" and is seen being test fired by Stella in the lab.
In "Veritas" (S05E01), plain clothed NYPD officers are seen with Heckler & Koch MP5A2s.
In "Turbulence" (S05E03), ESU officers are seen with Heckler & Koch MP5A2s while the CSIs investigate the murder aboard an airplane.
In "Pay Up" (S05E25), ESU officers are again seen with Heckler & Koch MP5A2s in preparation for the final attack on the kidnappers hideout.
In "Veritas" (S05E01), a plain clothed NYPD officer is seen with a Heckler & Koch MP5A2.
Heckler & Koch MP5A3 with Surefire 628 weaponlight - 9x19mmError creating thumbnail: File missingAn officer (in red) aims an MP5A3 at Joe as he is arrested. (S05E01)
MP40
In "Yahrezit" (S05E22), during a flashback, German SS officers are seen with MP40s.
In "Pay Up" (S05E25), a gunman is seen with an AK that he used to shoot at Flack, Danny and Mac. The AK is later seen in the ransom video for Dunbrook's son.
In "The Cost of Living" (S05E05), a custom pen gun which fires a "rimfire .22 caliber" used by the real James Sutton (Chad Faust). It is seen being reconstructed by Sheldon and Mac.
In "Enough" (S05E06), Det. Stella Bonasera (Melina Kanakaredes) uses a taser which resembles a modified Remington 870 and is also similar to the Taser X12. It fires what Stella identifies as a "wireless charge with 4 barbs that packs a 1500 volt punch for up to 20 seconds." (In reality, this type of modified Remington is used by police departments to fire beanbag rounds.)
In "Page Turner" (S05E02), officers in riot gear fire what are described by Det. Flack as "37mm soft rounds, bean bags" from an unknown launcher. It looks like a DefTech 37mm launcher but the tubes are not as long as tehy are on the DefTech.