Michael's (Shane West) weapon of choice is a SIG-Sauer P220. Nikita gets a hold of Michael's after she pulls a secondary weapon during a confrontation in the pilot episode. He uses it to execute Dadich as part of a Division plot to discredit his name as a terorrist aside from being a war criminal.
SIG-Sauer P226
Robby uses his sidearm to kill a Division guard leader before he uses it to take Alex hostage. Owen takes the P226 from Gill (Michael Cram), a CIA agent stationed in Chile, on a Hercules C-130 en route to the US. CIA analyst Ryan Fletcher is armed with this in Chile before he is forced to drop it after being held at gunpoint.
SIG-Sauer P228
Division agents appear to be using P228's at the party in the pilot episode. Nikita disarms one of them and fires it. She also uses one when she tries to "rescue" the Senator from Division custody.
SIG-Sauer P239
Seemingly Nikita's (Maggie Q) preferred weapon in the pilot is a SIG-Sauer P239. It is a two toned DAK model, appears to be dehorned and has what looks to be a Hogue wraparound grip. Owen uses one for a short time as his main sidearm when he was assigned by Division to be in Montreal, Quebec before he went rogue with Nikita.
Beretta 92FS
One of the bodyguards of Nikita's target early in the pilot fires a Beretta 92FS at Nikita. General Safwani's bodyguards also carry 92FS pistols. Roan (Rob Stewart), a Division assaisin uses a suppressed version throughout the episode as well. Thom uses it as his main sidearm as a Division agent. Alex carries a suppresed 92FS in "Coup De Grace" (S1E13).
Beretta 92FS Centurion
A Division agent uses one by forcing Jill to fire it in order to frame her in "Kill Jill".
Beretta 92FS INOX
Alex disarms a guard in the Zoman family estate in "All the Way".
Glock 17
Michael (Shane West) is seen with a Glock 17 when confronting Nikita in her memory, interestingly he never uses a Glock in reality. Police officers use Glock 17s in "Phoenix".
Glock 17 with a CAA Tactical RONI-G1
A Glock 17 on a mounted RONI-G1 can be barely seen with a shoulder sling on a Division operative after he and his team assassinate a chief editor to frame Jill. Sara (Alexandra Krosney) uses a RONI-G1 when she and Nikita fight off Division operatives. It is also the main weapon of Division operatives as a submachine gun/carbine-type weapon.
Glock 26
Nikita has a Glock 26 in her gun case. Evil Future Alex uses A Glock 26 in a dream sequnce in "Echoes" (S1E16)
Zoraki 914
On several occasions, Zoraki 914 blank firing pistols are used. These pistols are capable of semi automatic and full automatic fire, and are used to substitute for conventional pistols and machine pistols.
Zoraki 925
Nikita acquires a Zoraki 925 blank firing pistol fitted with an extended magazine from a guard in "Alexandra" (Season 1, episode 15).
Unknown pistols
Submachine Guns
Heckler & Koch MP5A3
Among other Division recruits, Alex (Lyndsy Fonseca), Jaden (Tiffany Hines), & Thom (Ashton Holmes) are seen assembling MP5A3's as part of their training. Rospeta mercenaries working under Hanna are armed with the MP5A3, some of them suppressed when they battled Michael and Division agents sent to assist him in the New York subways. A Division operative handles on in the arsenal prior to securing Jill.
Heckler & Koch MP5SD
Several MP5SD submachine guns are seen in a gun case in the background.
Heckler & Koch MP5K
Several MP5K submachine guns are seen in a gun case.
IMI Uzi
Nikita has a full size Uzi in her gun cache. Kasim Tariq's (Haaz Sleiman) bodyguards in Uzbekistan are also armed with Uzis.
FN P90
Division operatives use the P90 in "All the Way", going in to help Alex by assassinating Gaddiel Zoman in his estate.
FN P90TR
Several P90s are seen in the gun case as well. They are the TR version, fitted with EOTech 552 sights. Several P90TRs with the sights removed were used by a team of recruits in a CQB training simulation. Somehow almost all of the recruits manage to fit in a wild firing spree, most notably Alex (Lyndsy Fonseca). Used by Nikita and Owen when they go into Chile and rescue a CIA analyst from leftist guerrillas. A Division guard is armed with a P90TR before Nikita disarms him. Also used extensively by Gogol operatives in a firefight with Division.
Sa. Vz.61 Skorpion
One of the "kidnappers" in episode 6 uses a Sa. Vz.61 Skorpion during the bus attack.
Rifles
SIG SG 552
Division agents are seen with SIG SG 552s fitted with suppressors and C-More red dot sights in the pilot episode. The SIG SG 552 appears to be the stand-issue Division assault rifle and are used by Division personnel with and without the suppressor and dot sight. Percy uses one when he pursues Nikita and a wounded Owen in the port of Montreal.
IMI Compact Tavor CTAR-21
As well as the SIG SG 552, Division agents also use compact Tavor TAR-21s, fitted with suppressors and Meprolight Mepro 21 sights. It's later seen on Trevor's table, fitted with the same acessories.
Heckler & Koch G36C
A Heckler & Koch G36C is seen in Nikita's weapon cache. Owen borrows it when he retrieves the black box in Montreal. Several guards appear to be using them during Robby's rampage but only the stock is shown clearly, everything else is blocked by weaponlights aimed at the camera.
Zastava M70
Bank robbers in the opening to episode 5 use Zastava M70s, and Owen (Devon Sawa) seizes one to disrupt the robbery. Leftist guerrillas are armed with M70AB2s while in Chile.
M4A1
A M4A1 with a bipod, scope, laser sight and suppressor is seen on a table displayed by Nikita's arm dealer contact, Trevor. Other M4A1s fitted with M203 grenade launchers, are seen in the Division armory.
Unknown M16
M16A2-like rifles are used by US Army soldiers in the C-130 when Nikita and Owen disarm Gill of his weapon.
FAMAS G2
FAMAS G2 rifles are seen in the Division armory but have not been fired in the series.
Shotguns
Remington 870 Police
Used by a Division operative in "All the Way", sent in under Percy's order to assist Alex in her mission.
Serbu Super Shorty Remington 870 Shotgun
What appears to be a Serbu Super Shorty with a foregrip is carried by a robber in the fifth episode.
Unknown Shotguns
Two unknown shotguns are used by Alex and her accomplice(who was actually Nikita) in the drug store robbery in episode 1. I'm 97% sure Alex's is a Winchester 1300, but I'm not sure. And her accomplices is completely beyond me.
Sniper Rifles
Steyr HS.50
Nikita is seen using a Steyr HS.50 in the episode 2.0, acquired from an arms dealer named Trevor before she had a confrontation with him over killing her to get a reward from Percy. She uses it to snipe a Rospeta-linked mercenary attacking Michael.
Remington 700PSS
Michael uses a Remington 700 PSS sniper rifle when hunting down Kasim Tariq in Uzbekistan.
Others
X26 Taser
Seen in episode 7 when Alex takes a X26 Taser from Robby's holster and fires it to stun him before she takes him down.
RPG-22
Michael uses this in the Chile mission when he destroys a guerrilla-owned truck.