Stargate Atlantis was the first television spin-off of the series Stargate SG-1. Premiering on the Sci-Fi Channel in 2004 and airing for 5 seasons, the series followed an expedition sent by Stargate Command to Atlantis, a spaceship the size of a city located in the Pegasus Galaxy. The series would subsequently be followed by a second spin-off, Stargate Universe.
(This page is dedicated to the real world weapons and some fictional weapons which appear to be based on real world guns. This page does not list completely alien prop weapons.)
The following weapons were used in the television series Stargate: Atlantis:
The FN P90 is the standard submachine gun of the Atlantis expedition as it has been the staple weapon of the Stargate series. It is carried by most Marines and armed scientists including John Sheppard (Joe Flanigan).
Heckler & Koch MP7
The Heckler & Koch MP7 was used by the NID agents in "Outcast".
Heckler & Koch MP5A3
Heckler & Koch MP5K
The Beretta 92FS is the sidearm widely issued to both the military and civilian personal on Atlantis.
From Season 2, Sheppard is seen carrying an early version of the Para-Ordnance P-14 Limited over the standard-issue Beretta. During the first Season he used the Beretta M9 carried by most of the Atlantis expedition members.
In the Season 5 episode "Vegas", an alternate Sheppard uses a nickel M1911A1 with pearl grips.
Ronon uses a specialized pistol that looks like a heavily dressed up revolver. In the story it fires like a phaser, stun and kill with an extra option to blow a huge hole into things. Apparently in the story, the color of the gun changes according to whichever setting. A reddish orange for kill setting or "blow a nasty hole in the wall" setting and white for stun. There is also ammo for this weapon since in scenes where scenes of Ronon reloading his weapon and energy actually drained. According to concept art, the ammo is rechargeable, though the exact method is unclear.
Genii pistol - Dressed up Taurus PT99AF aka The Timecop Beretta
In the episode showing the people known as the Genii uses pistols that looked like dressed up Taurus PT99AFs. This pistol, aka the "Timecop Beretta" (due to their being first mocked up for the 1994 Jean-Claude Van Damme sci-fi film Timecop) was previously used in the Stargate SG-1 episode "Icon".
Smith & Wesson Schofield
Seen in the episode "Irresponsible" in the hands of a band of criminals.
Benelli MP95E Target Pistol
Dressed up Desert Eagle aka the Timecop Desert Eagle
Seen in the hands of the Genii all the time, but never any closeups of what this weapon really is. The video special on weapons of Atlantis reveals it's a heavily dressed up Desert Eagle. It was given a folding a vertical foregrip and sight on top. There is also a special cocking handle to cock the gun since the slide is buried within the dressing. According to the Armorer, Rob Fournier, it fires .44 Magnums.
One of these, equipped with an AN/PVS-14 sight, is carried briefly by Sheppard in the episode "Runner", Season 2, and is also picked up by Doctor Carson Beckett in the same episode, but is never used.
The GAU-5/A was the USAF contract version of the XM177 "CAR-15" short assault rifle. The real life USAF Security forces used them until recently, however, most of the non firing GAU-5/As seen in both Stargate: SG1 and Stargate: Atlantis were simply XM177E2 "Airsoft guns". No real GAU-5/As were used. All firing guns were mocked up AR15 Heavy Barreled carbines that were cut down and a fake XM177 style flash hider was welded on, and assembled with a registered full auto lower receiver. The Real GAU-5/A carbine did not have a heavy barrel.
USAF SFs in "Vegas" carry M16A2 rifles. From the white printed markings on the receiver (as opposed to the markings simply being stamped into the metal) and the fact that they are never fired, it is likely that these are Airsoft replicas.
Heckler & Koch G36K
Seen used by a few Marines, Major Lorne and notably in one episode by Teal'c and Ronon. Like Teal'c, we'd probably see Ronan with human guns more often, but with his infamous energy pistol blowing up walls, most likely not. G36K were used during firing scenes, while the export version G36KE were used in those instances were the production did not require live firing.
Norinco Type 97
Seen in the episode "Ghost in the Machine" after/during the part where Dr. Weir walks through the Stargate. Seen in the hands of a enlisted security officer up on an Atlantis balcony.
Norinco Type-97B Carbine
Daewoo K3 mocked up as M249
Contrary to popular belief, there are no real FN Minimi or M249 light machine guns used in Stargate: Atlantis or its sister show, Stargate: SG1. The light machine guns used by the Atlantis expedition are actually Korean-made Daewoo K3s that have been fitted with M249 Paratrooper-style stocks and shortened barrels, as well as RIS rails and vertical grips similar to those seen on the Mk 46 Mod 0. These weapons were used most notably in the Season 2 episode "Duet" where several were used to shoot down a Wraith Dart.
M2 Browning .50 Caliber
Several of these can be seen mounted on pintle mounts being used as anti-aircraft weapons in the Season 1 episode "The Siege".
Seen on Atlantis when Weir returned as a replicator in the Season 5 episodes "First Contact" and "Ghost in the Machine".
Benelli M1 Super 90
Seen with integrated lit fore grips in "Outcast", Season 4.
The Mossberg 500 is used by Lieutenant Colonel John Sheppard in the Season 4 episode "Outcast".
Double barrel shotgun
Double barrel shotguns are seen in many episodes.
Krieghoff Model L
Another weapon that was also seen in (Blade: Trinity & Blade: The Series), a WWII flare gun converted to a shotgun. The Genii can be seen using the dressed up weapon as used in the Blade series, however Ronan can be seen using an unmodified version of the flare gun.
"Bone Jack" (mocked up Winchester Model 1887)
Various character use heavily modified Winchester Model 1887 lever action shotguns with three fake shotgun barrels on them. It makes it seem like this is a one cock and fire several time, but it could be the trick of camera shots. It isn't clear if this is supposed to be a rifle or a shotgun. This prop was seen used in the 2004 film Blade: Trinity where it was known as the "Bone Jack".
The Armsel Protecta is seen in the hands of the Genii and also a Setadan weapon. Ronon used it in the episode "Seteda".
M67 hand grenade
The M67 hand grenade is used by Major Leonard in "Phantoms", Season 3.
AT-4 Rocket Launcher
Like in the previous series, this rocket launcher was misused as an anti air launcher to take out a Wraith Dart. In the following shot, Major Lorne (Kavan Smith) doesn't bother to pop up the sights to fire, which is understandable. The M136 AT4 sights are notorious for being difficult to deploy when the plastic sliding sight covers 'stick', and in the stress of battle, they've been fired a lot just 'point and shoot'.
A video about the Weapons of Atlantis from the Armorer. http://www.youtube.com/watch?v=ZIR_UCp6fPo