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).
A Calico M955A with 100 round helical magazine appears in the hands of a Lucian Alliance guard in "Off the Grid" (Season 9, Episode 16), equipped with what seems to be a laser aiming module.
SG-1 were first seen using MP7s when impersonating non-Earth humans, rather than their more distinctive P90s. Since then, the MP7 has not been seen in used by the SG teams and only a handful of extras are seen holding them.
In the episode "Off the Grid" (Season 9, Episode 16), Worrel (Vince Corazza) uses a MAC-10 for a couple of scenes before taking one of SG-1's MP7s. The barrel attachment is of a similar build to the one used on Blade and Blade II.
A thug in the episode "Off the Grid" (Season 9, Episode 16) holds a modified Steyr SPP pistol with factory rails, Aimpoint sight and custom flash hider.
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.
Usually seen carried by the Cheyenne Mountain guards in stock footage.
Error creating thumbnail: File missingM16A1 with 30 Round magazine - 5.56x45mmError creating thumbnail: File missingNever understood why the guy on the left always seem to hold onto his M16 slung behind him, as if to keep it from swinging around. Isn't that what slinging your rifle on your back is for? The point is so it doesn't swing around and bother you.Error creating thumbnail: File missingTwo guards with M16A1 rifles in stock footage guarding the entrance to Cheyenne Mountain.
M4A1
One of the primary weapons utilized by the Stargate teams. During later seasons they are rarely seen without any attachments, mostly being equipped with flashlights, Cobray flare launchers and laser aiming modules. A small side note for the interested reader: The lower handguard on the M4 has to be removed in order to accommodate underbarrel grenade launchers like the M203 or, in this case, the Cobray 37mm Launcher.
These two guns were set up in the gate room but were never used in the 10 years the show ran for. The M2 was also used at the Alpha site in "Allegiance" (Season 6, Episode 9), but was - once again - not fired. The weapon was then seen in "Bad Guys" (Season 10, Episode 16), mounted on an APC used by the alien security forces. The only instance were the weapon saw actual combat was in "Forever in a Day" (Season 3, Episode 10), were it was mounted on a F.R.E.D. during the onslaught of Heru'ur´s Jaffa.
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.
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.
