Stargate SG-1 - Season 4
The following weapons were used in Season 4 of the television series Stargate SG-1:
The most common sidearm seen in used by the SG teams (although in real life, the M9 is the military designation for the Beretta, the prop weapons used in the show are most likely the civilian Beretta 92FS).
Beretta 92FS Inox
The Beretta 92FS Inox appears in the episode "Absolute Power" (Season 4, Episode 17), carried by Daniel Jackson's bodyguards at his estate.
(Mock-up) Beretta M93R
Machine pistols with the appearance of Beretta 93Rs are seen in a number of episodes being used by US Secret Service agents, and the Trust agent Hoskins. If you look closely, you can see that they have the slide-mounted safety/de-cocker switch, whereas the 93R has it mounted on the frame. That means they're actually Beretta 92FS dressed up to resemble M93Rs (with fake forward grips and flash hiders) and probably converted to auto with drop-in units; identical guns have also appeared in Harsh Realm and I, Robot (which were both done by the same armourers who worked on this show).
A stainless steel Ruger P89 is used by one of Dr. Tanner's associates in the episode "Point of No Return" (Season 4, Episode 11).
First seen in "Chain Reaction" (Season 4, Episode 15). O'Neill (Richard Dean Anderson) is seen taking it off an NID agent.
FN P90 Personal Defence Weapon
The FN P90 became the most common weapon used by Stargate teams after its introduction in "The First Ones" (Season 4, Episode 8). In the episode that introduced it, O'Neill suggested using the weapon because the ammo was better at penetrating than the MP5. We can assume it was just a device in the script to bring this weapon into the fold, which is rare since there aren't that many series that actually brings up a weapon for the sake of the plot. This is the weapon that is identified when anyone thinks of of the Stargate series. The series probably picked this weapon for its futuristic look, something that sets it apart from many other weapons at the time. It is also likely the budget allowed for the expensive ammunition that comes with a P90, even blanks would cost a lot of money. Dan Shea, series stunt coordinator (1997-2007), has stated one reason the P90 was chosen is that it ejects the empty brass straight down when firing; this allows positioning of actors in a scene without worrying where expended cartridges will be flying. In addition, the weapon is ambidextrous in design, so both right- or left-handed shooters can handle it without problem.
In a few episodes, particularly in the later seasons, Teal'c has been seen dual wielding this SMG, probably because he was not trained in standard practices of Earth military. However, in Stargate: Continuum, Colonel Cameron Mitchell was also seen dual wielding P90s. The weapon was also used on one occasion by Bra'tac and often seen in the hands the Free Jaffa. The P90 was introduced to the Free Jaffa in Season 5 episode "The Warrior". In most subsequent episodes with the free Jaffa we see them using this weapon instead of the Jaffa's traditional staff weapons.
Heckler & Koch MP5A3
The Heckler & Koch MP5A3, almost exclusively equipped with the Surefire dedicated forend weaponlight, is the primary weapon used by all SG teams for the first few seasons. Then when the main cast and some supporting and extras switched to the P90, the MP5 became less common. Also seen in use by the Free Jaffa Nation later in the series. MP5 also makes a small comeback when we see them again in the hands of a special assault unit raiding a Trust compound. Throughout the series it is generally the case that for non firing scenes the actors carry airsoft replica MP5s with a Navy trigger group, whereas for firing scenes their weapons switch to real firearms with SEF trigger groups.
Heckler & Koch MP5K
MP5Ks are used by NID agents in "Chain Reaction" (Season 4, Episode 15).
Seen being used by Secret Service agents in "Divide and Conquer" (Season 4, Episode 5) and by NID agents in "Chain Reaction" (Season 4, Episode 15).
USAS-12 Assault Shotgun
This assault shotgun is seen mostly in the episodes featuring the Replicators, but actually had its very first appearance in the first episode "Children of the Gods" (Season 1, Episode 1). The USAS-12 shotguns in SG1 are newer CQ versions with a modified carry handle, no front sight and shortened barrel (sometimes with a muzzle brake).
Diemaco C7/Olympic K4B
Seen used by Marines, and the security of Stargate Command. These are all Olympic Arms K4B rifles (same receiver style as the Colt Model 715/Diemaco C7), standing in for the M16A2.
GAU-5/A and GAU-5A/A
The GAU-5/A and GAU-5A/A were the USAF contract versions of the XM177 and XM177E2 "CAR-15" short assault rifle. The USAF Security forces used them until recently, however, most of the non firing GAU-5A/As seen in the show were simply XM177E2 "Airsoft guns". The actual GAU-5A/A carbines look like the XM177E2 but don't have forward Assist buttons.
The GAU-5 variants that appeared on the show seem to be a mix of full-auto converted Colt AR-15 SP1s and Olympic Arms K3Bs, all with chopped barrels and fake GAU-5 flash hiders installed. The converted AR-15 SP1s have the "slab-side" receiver, while the K3Bs are recognizable by their 715-style receiver (forward assist, brass deflector, A1-style rear sight) and "Stowaway" pistol grips.
Usually seen carried by the Cheyenne Mountain guards in stock footage. The weapons most prominent appearance is in "2010" (Season 4, Episode 16), used by a color guard, with A2 forearms.
These two guns were set up in the gate room but were never used in the 10 years the show ran for.
Daewoo K3 (mocked up as M249)
Contrary to popular belief, there are no real FN Minimi or M249 light machine guns used in Stargate: SG1 or its sister show, Stargate: Atlantis. The light machine guns used by the SG teams are actually Korean-made Daewoo K3s that have been fitted with M249 Paratrooper-style stocks and shortened barrels. Some of the K3s seen on the show also have RIS rails and vertical grips similar to those seen on the Mk 46 Mod 0.
Cobray CM203 Flare Launcher
Seen attached to M4s and M16s. Prop wise, these were all Cobray 37mm flare launchers meant to mimic the appearance of an M203. What tips them off is the absence of a second trigger, the shape of the trigger guard, the lack of a step up in the receiver, and the cocking lever on the SIDE of the receiver.