Go West (1940)

A Western parody with Groucho as S. Quentin Quale, a con man heading west to look for gold, whom Chico and Harpo cheat out of his money before the three end up in the middle of a feud between two families. That early hustle, with each of them trying to out-swindle the others, is the brothers working at full speed. After it, the plot about land and rival developers takes over and the jokes come less often. Of the late MGM films it is the liveliest and the best next step once you have run through the top seven and want more.