You guys are too young to have seen THE LAST SUNSET, a movie produced in 1961, with Kirk Douglas & Co. Its title over here was DUEL AT THE SUNSET.
This is how it ends:
" On the eve of the showdown between the two men, Belle discloses the secret that Missy is the daughter of O'Malley and their incestuous love cannot continue. At the gunfight, O'Malley faces the sheriff with an unloaded gun,
effectively committing suicide."
Eventually O'Malley dressed in black and always carried a Derringer ... which takes us back to old weapons discussions