The 1939 classic "Stagecoach," starring John Wayne, featured the local marshal talking about riding shotgun; a 1954 flick titled "Riding Shotgun" starred Randolph Scott as a stagecoach guard.

The guards' preferred weapon was a shotgun, which scatters pellets, making it relatively easy to hit your target at close range. This poster for the 1954 movie "Riding Shotgun" spells the plot out ...