Warlock

Director Edward Dmytryk writes in his autobiography that Henry Fonda was such a fast draw with his six shooter that he (Dmytryk) had to slow down the action so the audience could savor it properly.

Before the shootout with Billy, Morgan sees Calhoun and fires once to stop him, with the second shot heard coming from Calhoun's rifle. All of the other gunshots heard or seen were from the participants of the shootout. After the shootout, someone says Calhoun was shot three times, once in the throat and twice in the chest. Morgan says he aimed all three shots at his chest. He could not have shot him three times since he only fired once.

This is just gunman braggadocio. Bragging and self-aggrandizing are normal behaviour. However, since only three shots were fired in the opening salvo, with two bodies as a result, there is a shooter missing, who had a lucky coincidence of putting the extra two holes in Calhoun simultaneously with the sound of two of the other shots.