Charlton Heston speaks through gritted teeth as Buffalo Bill Cody, Forrest Tucker reminds us of what a solid supporting actor he could be as Wild Bill Hickock and Rhonda Fleming plays one of those naughty but nice girls she made her specialty. All that is very well and good but there are long dull stretches with tepid dialogue and little or no action to speak of. Jan Sterling appears as the tomboy whose love for Buffalo Bill is unrequited and hers is one of the most grating performances in Western movie history. The screenwriters probably thought of Annie Oakley, but rather than gritty and comedic, Lassie's mother comes across as a whiny child who is constantly (and blessedly) told to "shut up." The Arizona locations are as magnificent as Miss Fleming's titian tresses, of course, and the climactic ride to the rescue -- of California, no less -- is thrilling enough, but Pony Express is more lukewarm mythmaking than a colorful page from the history books.