The Western movie is a continuation of Stephen King's novel of the same name.
Elba says he was doubtful about the role as he did not want to glorify gun violence, reported Femalefirst.
"I had a clash of conscience with my character. In America, there's a real awareness of gun culture. I had to break down why he's good at shooting.
"We erred on the side of 'This is his tool. It's set in this world that's part of Stephen King's imagination, and it is what it is...," the 44-year-old actor says.
"I'll probably be crucified by the film company for even mentioning this," he says.