Blood Simple.

The following firearms were use in the film Blood Simple.:

Note: Just like Snatch., the title is spelt with a period. In order not to reveal any spoilers, the descriptions will be brief.

Blood Simple. - Directed by Joel and Ethan Coen. This was thief first film.

Iver Johnson Revolver

The most common weapon in the film is an Iver Johnson revolver. It is first kept by Abby (Frances McDormand) as a personal defense weapon, but is also used by her husband Marty (Dan Hedaya) and her lover Ray (John Getz), as well as the Private Investigator (M. Emmet Walsh). (Note: On IMDb and in the Coen brother's screenplay, his name is revealed as Loren Visser, but this does not come up in the film.)

Iver Johnson - .32 Smith & Wesson

Abby reaches for the revolver as Marty attacks her

The revolver is found in Abby's handbag by the private investigator

The revolver is held by the private investigator

The Iver Johnson on the ground

The pistol is aimed at Ray, but it is unloaded

Abby with the revolver in the final scene

M1911

An M1911 is the sidearm of the private investigator, but not seen until the final scene.

M1911 - .45 ACP

The private investigator drops his pistol

Bolt-Action Scoped Rifle

The private investigator uses an unknown type of bolt-action rifle to take aim at Abby and Ray.

Unknown Smith & Wesson revolver

In an apparent continuity error, a different revolver is seen in Abby's handbag. It has a Smith & Wesson logo.

Extra

Looking closely, the box of bullets can be seen with "Blanks" written on it