Ripstein produced the film with Mexican director Michel Franco. The screenplay, by Ripstein and Issa López, was inspired by the ATF gunwalking scandal. Ripstein wanted to focus the story on the two characters, rather than expanding it to include the cartel leaders. He attempted to express his view of guns "objectively, almost like a documentarian", since he has been exposed to guns from an early age; his grandfather took him and his brother shooting on weekends, and "my brother became an exceptional shot; they hunted ducks and my grandmother cooked them".