In the 1962 movie The Man Who Shot Liberty Valance, tenderfoot lawyer Ransome Stoddard, played by James Stewart, runs afoul of the local desperado bully, Liberty Valance played by Lee Marvin. Determined to stick it out, he eventually buys a gun to protect himself but has no idea how to use it. Here, gunfighter Tom Donophon played by John Wayne offers him a bit of instruction.
It's a great movie with an all-star cast. Valance's two henchmen are played by http://en.wikipedia.org/wiki/Lee_Van_Cleef and Strother Martin. Donophon's right hand man was played by Woody Strode, a then-famous athlete-turned-actor. Other stars of the day such as Andy Devine, Edmund O'Brien, John Carradine and Denver Pyle can be seen in this one, too, along with a then-hot Vera Miles as the lady that Donophon pursued but Stoddard won.
And here's the epic gunfight from the showdown between Stoddard and Valance.
I won't spoil a great movie by giving too much away, but if you haven't seen it, you need to.