The following weapons were used in the film Home Alone:
Smith & Wesson Model 10 Revolver
Several Chicago police officers are seen carrying what appears to be a Smith & Wesson Model 10 revolver in their holsters. Harry Lyme (Joe Pesci) also carries a revolver when he's impersonating an officer.
Colt 1921AC Thompson
When Kevin McCallister (Macaulay Culkin) watches a gangster movie titled "Angels with Filthy Souls", he sees Johnny (Ralph Foody) use a Colt 1921AC Thompson loaded with a 50-round drum magazine to mow down another gangster nicknamed "Snakes".
Pump Action BB Gun
Kevin is also seen using his brother Buzz's Pump Action BB Gun throughout the film. He first uses it to shoot at action figures arranged as part of a makeshift shooting gallery he sets up, then later on he turns it on the Wet Bandits when they're trying to break into his house.