The following weapons were seen in Quack Experimental Anime: Excel Saga:
Smith & Wesson Model 686
A Smith & Wesson Model 686 is used by a rebel in the third episode of Excel Saga for a blindfolded target practice.
The main sidearm of the rebels is the M1911A1.
IMI Desert Eagle
The Mayors head Accountant/Assassin carries a IMI Desert Eagle.
Prototype Laser Gun Ver. 1
A prototype laser gun is used by the Department of City Security. Given the unstable output (one shot nearly destroyed a mountain and caused an avalanche) it was quickly replaced by the Mark 2.
Antonio, Excel and Hyatts' temporary boss and friend of Nabeshin owns a Beretta 92F.
In one of Iwata's daydreams, he is armed with a nondescript generic revolver.
Walther P38 (Lighter)
Nabeshin has a lighter that is disguised as a Walther P38.
Winchester Model 1897
Some rebels were armed with Winchester Model 1897 shotguns, telling by the more squarer size trigger guard and the shape of the receiver. Nabeshin pulls another Winchester Model 1897 out of his afro and gives it to Excel.
The evil dogs in episode 10 carry Franchi SPAS-12 shotguns.
Bowling Pin Gun
An odd gun used by bowling loving terrorists.
The main weapon of the rebels is the M16A1.
Antonio sends Excel out hunting with a scoped AKS-74U, which appears to have a synthetic grip and handguard.
Prototype Laser Gun Ver. 2
The M41A Pulse Rifle from Aliens is used in the 7th episode (which spoofs the Alien franchise and other thriller movies/animes). It was the second version of the prototype Laser Gun (the first being the above entry). It notably features a full stock with a large "2" written on the side.
One of the rebel jeeps has a Browning M1919A5 mounted on it, as noted by its downward curving bolt retracting bar.
M60E4 Machine Gun
Nabeshin has a M60E4 machine gun hidden in his afro.
General Dynamics M197 Vulcan
A General Dynamics M197 Vulcan is seen on a helicopter being flown by the head rebel.