Boot Hill (1975)

From the cover of the rulebook:

Rules for "Wild West" gunfights and campaigns with miniature figures on a man-to-man scale.

From the foreword in the rulebook:

These rules are aimed at enjoyment on a plane unusual to wargaming, the individual and personal. Rather than commanding hordes of troops players typically have but a single figure, their "character". With these figures the players recreate the individual gunfights, saloon brawls, and Wild West action as has come down to us from the pages of history - and the celluloid of Hollywood Westerns.