Sgt. Joe Gavilan (Harrison Ford) carries a Smith & Wesson 410S, the stainless model of the .40 caliber Smith & Wesson 410 as his sidearm throughout the film.
Beretta 92FS
Det. K.C. Calden (Josh Hartnett) keeps a Beretta 92FS as his sidearm throughout the film. LAPD officers are also seen issued with Berettas, and one of which is stolen by a criminal being arrested, who fires it around the police parking lot with his hands behind his back. K.C counts the shots he fires and goes to jump him after 15 shots (which if closely counted is the full 16 shots), only to be shown by Joe that the gun still has "One in the 'spout'", meaning one still loaded in the chamber.
Heckler & Koch MP5A3
Several gangsters during the beginning of the film mow down 4 rappers with H&K MP5A3 submachine guns fitted with RIS foregrips and M68 Aimpoint scopes. They look to have Navy style trigger groups.