Firepower (1979)

aka: Fire Power

Adele Tasca (Sophia Loren) is convinced that her late spouse, a chemist, was murdered by a filthy rich, reclusive entrepreneur, Stegner (Anthony Franciosa). When she reports her suspicions to the authorities at the U.S. Justice Department, the officials squeeze mobster Sal Hyman (Eli Wallach) to put a contract out on Stegner. Hyman, in turn, persuades retiree gunsmith Jerry Fanon (James Coburn) and his assistant Catlett (O.J. Simpson) to bring down Stegner once and for all. Also with Billy Barty, ex-boxer Jake LaMotta and Victor Mature.