Even though Machine Gun McCain was an Italian production, most of the film was shot on location in Las Vegas with some location shooting in Rome, New York, San Francisco and Los Angeles.

John Cassavetes had agreed to star in Machine Gun McCain after unsuccessfully shopping around his Husbands (1970) project in Hollywood. Even though his previous film Faces (1968) had been a critical and commercial success, Cassavetes realized that every studio viewed Husbands as a completely uncommercial endeavor. So instead, he approached Bino Cicogna, head of Euro International, and the producer of Machine Gun McCain as a possible investor.

Cicogna, who also produced Sergio Leone's Once Upon a Time in the West (1968), was a tall, elegant looking man with a quiet demeanor, a facade that contrasted with his often suspect business dealings. He eventually would flee Europe and his creditors for the safety of Brazil but in 1968 he was quite open to the idea of financing a film by Cassavetes, especially since Faces had performed so well in Europe, making the young director a cause celebre.

According to Marshall Fine's biography, Accidental Genius: How John Cassavetes Invented American Independent Film, "the opportunity to produce what sounded like a prestige film with American stars, directed by a rising American filmmaker, looked like a foot in the door to Hollywood legitimacy. Cicogna was only too happy to commit his funding - to the tune of $1.5 million - and to cede all artistic control to Cassavetes. The contract Cassavetes had worked out with Cicogna, Al Ruban recalled, "was totally in our favor. Contractually, they had nothing to say." Thus, thanks to Cicogna and Cassavetes' involvement in Machine Gun McCain, Husbands became a reality.

While Cassavetes and Peter Falk were filming Machine Gun McCain, they would work on refining the Husbands screenplay with input from Ben Gazzara who was cast as the third major character in the movie's central trio. At the time Gazzara was in Prague working on The Bridge at Remagen (1969) while Cassavetes and Falk were in Rome for some location shooting for Machine Gun McCain. When Russian troops invaded Czechoslovakia - known as the "Prague Spring" - Cassavetes and Falk were worried about Gazzara's safety but their colleague avoided any dangerous situations and was soon reunited with his friends.

Due to Cassavetes' involvement in Machine Gun McCain, his wife, Gena Rowlands, was cast in a pivotal cameo role in the film as Rosemary, a former lover of McCain who he turns to for help when mafia hitmen pursue him. In their brief scenes together, Cassavetes and Rowlands display the sort of spontaneous, improvised acting that was already a distinguishing feature of Cassavetes' movies.

by Jeff Stafford