The following firearms were used in the film Se7en:
Se7en is a 1995 police crime thriller following two detectives, one new to the job, the other on the verge of retiring as they try to crack the case of a murderer who uses the Seven Deadly Sins (Gluttony, Greed, Sloth, Lust, Pride, Envy, and Wrath) as his inspiration. The film's setting is intentionally never told, as the city is supposed to be a fictional, more noir version of New York City. Police Technical Advisors where on the set at all times to correct the actors, which explains the exceptional gun handling seen throughout the film.
Detective David Mills (Brad Pitt) uses a customized Springfield Armory M1911-A1 with adjustable sights, mag-na-ported/bushingless bull barrel, beavertail grip safety, ring hammer, extended slide stop safety, extended slide release, light-weight 3-hole trigger, square trigger guard, and stag horn grips as his sidearm throughout the film, notabley during the climax.
Taurus PT99 AF
A blued Taurus PT99 AF with wood grips is used by John Doe (Kevin Spacey) when Detective Mills (Brad Pitt) and Detective Lt. William Somerset (Morgan Freeman) go to his apartment, and ultimately holds it on Mills before sparing his life. One of the murder victims is described as having bruises from the muzzle and front sight of Doe's pistol on their head, which seems unlikely since the barrel protrudes significantly past the muzzle, distancing the front sight from the barrel. One could argue however he cants the gun at a slight angle when he holds it on people, and in the first victims case, he had 12 hours of time to push different parts of the muzzle enough to discern it was used.
Heckler & Koch MP5A2 Navy
Heckler & Koch MP5A2s with Navy trigger groups and Surefire 628 forend weaponlights are used by the SWAT team when they breach the apartment and find the third victim of John Doe's (Kevin Spacey) killing spree.
Mossberg 590
Some of the SWAT members, notabley California (John C. McGinley), wield Mossberg 590 shotguns with tactical flashlights when breaching the apartment of the third victim. One is fitted with ghost-ring sights.
Colt AR-15 A2 Sporter HBAR
A SWAT team member is seen with a Colt AR-15 A2 Sporter HBAR slung over his back. This is the civilian version of the M16A2.
M1911A1
The SWAT team members are seen with unknown M1911A1-series pistols in their tac-vest holstrs. Since SWAT team 1911 models varied heavily in the '90s, they could be multiple types.
Glock 17
The police officers in the film carry Glock 17s as their issued sidearms.