Moe (Moe Howard) carries an unknown type of Sharps Carbine in the episode "Rockin' Thru the Rockies" (1940). Curly (Curly Howard) also uses the rifle to accidentally shoot three ducks with one shot.
Krag-Jørgensen
Curly uses a Krag-Jørgensen rifle in the episode "Spook Louder" (1943).
Winchester 1894
The Winchester 1894 appears in both "Dizzy Pilots" (1943; used by Curly) and in "Guns-a-Poppin" (1957; used by Moe).
M1903 Springfield
Curly makes use of what looks like an M1903 Springfield rifle in "Three Pests in a Mess" (1945).
Trapdoor Springfield Rifle
Larry, Curly and Moe are issued Trapdoor Springfield Rifles in "Boobs in Arms" (1940). The Springfield is also used heavily in "Uncivil War Birds" by just about everyone.
Shotguns
Unidentified side-by-side shotgun
Curly uses an unidentified double barreled shotgun in "Dizzy Pilots" (1943) after Larry points out he might miss with the rifle. A couple are also used by Larry and Curly in "Idiots Deluxe" (1945) for trying to deal with a loose bear.
Winchester Model 1897
Larry uses a Winchester Model 1897 in "Shot on the Frontier" (1954). Unfortunately he mistakenly loads hot dogs rather than shells when acquiring it. Moe also uses a Winchester Model 1897 in "A Ducking They Did Go" (1939).
Handguns
Single Action Army
A detective has a drawer full of five artillery model Single Action Army revolvers in "Dopey Dicks" (1950), along with a couple of others.
Colt Police Positive
What looks like a Colt Police Positive is present in the detective's drawer in "Dopey Dicks" (1950).
Iver Johnson Revolver
A pearl gripped Iver Johnson Revolver is seen in the drawer guns in "Dopey Dicks" (1950) as well.
An Iver Johnson Revolver is also seen wielded by a trained monkey in "Tricky Dicks" (1953).
Colt Lightning
Larry is seen trying to load a Colt Lightning in "Guns A-Poppin!" (1957) without much success.
Submachine guns
M1928A1 Thompson
Igor the Gorilla uses an M1928A1 Thompson in "A Bird in the Head" (1946). Igor fires the weapon semiautomatically.