Once Upon A Time In AmericaOnce Upon A Time In America - Internet Movie Firearms Database - Guns in Movies, TV and Video GamesOnce Upon A Time In America
One of the Syndicate mobsters, Beefy (Frank Gio), in the beginning of the film searches for Noodles with a Smith & Wesson Model 10. Patrick "Patsy" Goldberg (James Hayden) also carries a Model 10 in addition to his P210, most notably using it to kill Joe Minoldi (Burt Young) with a bullet in the eye, and holding it to the head of Crowning (Gerard Murphy).
SIG P210
One of the Syndicate mobsters, Trigger (Ray Dittrich), searching for Noodles uses a suppressed SIG P210 to kill Eve (Darlanne Fluegel). Patrick "Patsy" Goldberg (James Hayden) also carries one with his New Service on several occasions. (This is a major anachronism as this sequence of the film takes place in 1933 and the P210 wasn't developed until 1949).
FN Model 1910
David "Noodles" Aaronson (Robert De Niro) draws and fires a FN Model 1910 to kill the mobster guarding Fat Moe in 1933.
Colt Official Police
Bugsy (James Russo) uses a Colt Official Police to kill Dominic (Noah Moazezi) just before Noodles stabs him to death in 1921. (Anachronism as the Official Police wasn't developed until 1927).
Max Bercovicz (James Woods) shoots up Joe's car with a Thompson M1928 after the diamond heist. "Chicken Joe" (Richard Bright) later uses one during the attempted assassination of James Conway O'Donnell (Treat Williams). Noodles and Max's hitmen subsequently uses Thompsons to kill Chicken Joe and one of his associates.
M1911A1
Philip "Cockeye" Stein (William Forsythe) uses a M1911A1 to shoot up Joe's car after the diamond heist.
The bore aperture looks way too small to be a .45 ACP pistol, more likely a 9mm. If I had to guess, I'd say this is most likely a Star Model B, which is often used to double for the 1911 in movies. It might also be a Colt Series 70 in 9mm, but the former is more likely. -MT2008
In 1968, Secretary Christopher Bailey/Max Bercovicz (James Woods) gives David "Noodles" Aaronson a Smith & Wesson Bodyguard to exact his revenge with, but Noodles turns him down.