Section One is the most covert anti-terrorist organization in the world. It's purpose is to stop terrorism at all cost and they are good at what they do. "If we start making exceptions, we will be no better than the CIA"-Operations.
Flash paper versions of the onyx are used frequently after season 2, with alot of close up shots. Used ridicously, since the bad guys are using real blank firing guns.
MP5SD5 used when the mission calls for a little stealth.
Most MP5SDs in the show are actually UHC airsoft guns, you can tell by the molded finger swell on the fore grip.
H&K SP89
Shown in the opening credits
Mac 10
Used through the series.
Season 1, Episode 8 uses a toy squirt gun as a stand in. Really noticable.
Uzi
Sometimes depicted with Sonics noise suppresor
Mini Uzi
Often without the stock attached
Micro Uzi
Shown with red dot scope
Walther MPL
USed in season 2 by holographic enemy in the training simulator
CZ Skorpion
Tommy Gun
MP40
Seen breifly but not fired.
Sterling SMG
Assault Rifles
M16
M16A1 Carbine
Has forward assist and no case deflector
XM177
Add image
Colt Commando
G3
AKS 47
used mostly by the enemy and third world government agents.
AKM
Steyr AUG
Nikita showing the recruits the AUG.
Recruit demonstrates his 'skill' with the weapon, having played first person shooter his whole life.
SA 80
Machineguns
M60
Mounted on a pintelin the back of a jeep
Rocket Launchers
M72 LAW
AT4 (M136)
The AT4 is shown relatively few times throughout the series, most notably in Episode 2, in the hands of a Legion assassin trying to take out a privat jet.