One of the hoods sent by Joey Zasa to kill Vincent Mancini (Andy Garcia) carries a Beretta Cheetah, which Vincent disarms him of and uses to shoot both hoods. (Although the pistol turns into an Astra Constable for a close-up).
Astra Constable
For the close-up in which Vincent shoots the thug through the head, an Astra Constable replaces the Beretta Cheetah.
IMI Uzi
The helicopter hitmen sent by Joey Zasa (Joe Mantegna) to kill Michael Corleone (Al Pacino) and other mob bosses at the Atlantic City meeting carry Uzi submachine guns.
double-barreled shotgun
Several 12 Gauge Double Barreled Shotguns with exposed hammers can be seen. Al Neri (Richard Bright) uses one to blast out of the Atlantic City meeting, one of Vincent's hitmen uses one during the street parade shooting, Mosca (Mario Donatone) uses one when shooting at Don Tommasino's car, and some of the actors during Anthony's opera in Sicily can be seen handling some.
MAC-10
One of Vincent's hitmen during the street parade hit carries a MAC-10.
Colt revolver
While dressed as an NYPD officer on horseback, Vincent Mancini (Andy Garcia) uses a Colt revolver to shoot Joey Zasa.
Frederick Keinszig (Helmut Berger) keeps a Walther P38 as his personal sidearm when he goes on the run from the mob.
Browning Hi-Power
Mosca (Mario Donatone) fires two shots from a Browning Hi-Power at the end of the film while on the opera steps, in his final attempt to kill Michael Corleone (Al Pacino), but kills his daugther, Mary (Sofia Coppola).