The SIG-Sauer P228 is the main sidearm of nearly all the NCIS agents in the series including Special Agents Leroy Jethro Gibbs (Mark Harmon), Anthony DiNozzo (Michael Weatherly), Timothy McGee (Sean Murray), and Ziva David (Cote de Pablo). CGIS (Coast Guard Investigative Service) Special Agents Abigail Borin (Diane Neal) and Kyle Omagi (Eddie Shin) also are seen carrying SIG-Sauer P228's in Season 7's "Jurisdiction", although they would in reality carry a P239 DAK or a P229 DAK in some cases.
In Season 7's "Jack Knife", Ziva is seen carrying an AMT Backup pistol in an ankle holster.
Beretta 92FS
The Beretta 92FS (used in lieu of the Beretta M9) appears as the issued sidearm of various military personnel and in the hands of various characters throughout the series.
Beretta 92FS Inox
A Beretta 92FS Inox with pearl grips is used by the first mate on the Damocles in Season 7's "Good Cop, Bad Cop".
In Season 7's "Jack Knife", former Marine Damon Werth (Paul Telfer) is seen carrying a Colt, which is put on a table when he's searched.
Glock 17
The Glock 17 is another frequently-used handgun in the series. Ziva is seen using a Glock in Season 7's "Good Cop, Bad Cop". Ex-Army Ranger-turned-mercenary Jason Paul Dean (Dylan Bruno) pulls his Glock 17 on Gibbs after his arrival in Mexico in Season 7's "Patriot Down" (S7E23).
Glock 19
The Glock 19 is used by numerous characters in the series.
In "Good Cop, Bad Cop" (S7E04), the captain of the merchant ship Damocles uses the Jericho 941, almost shooting his first mate and holding it on Ziva before being shot from behind.
Smith & Wesson SW1911PD
Mike Franks (Muse Watson) carries a Smith & Wesson SW1911PD with the full 5" barrel as his sidearm. What differentiates the PD model are the front serrations on the slide that's similar to those in such handguns as the Kimber. The pistol also has a desert tan Crimson Trace grip-mounted laser sight. The SW1911PD is also used in the season 7 finale "Rule Fifty-One".
Tower Lancers Pistol
In Season 7's "Reunion", a 19th Century Tower Lancers Pistol is used by a suspect to shoot a man that the NCIS team was looking for.
Submachine Guns
FN P90
Mossad Officer Malachi Ben-Gidon (T.J. Ramini) uses an FN P90 during the firefight on the Damocles in Season 7's "Good Cop, Bad Cop". Two P90s are also visible in the "sanctuary" in Season 7's "Power Down".
Heckler & Koch MP5K
The three men that accompany Jason Dean to the airport in the Season 7 finale "Rule Fifty-One" use Heckler & Koch MP5Ks during the ensuing shootout.
A Winchester Model 1873 rifle is owned by Jackson Gibbs (Ralph Waite), who keeps it loaded on the wall. In Season 7's "Faith", Jackson mentions that he had to use his Winchester to kill someone trying to rob his store.
Sniper Rifles
Heckler & Koch SL8
Ziva can be seen using a suppressed SL8 in the season 7 episode "Rule Fifty-One". She uses it to provide sniper cover when DiNozzo and McGee try to arrest Jason Paul Dean (Dylan Bruno).
M40A1 Sniper Rifle
An M40A1 sniper rifle was the rifle used by Gibbs in his Marine days and he now keeps it in a case in his basement. He appears to use the rifle in Season 7's premiere "Truth or Consequences" (S07E01).