Shooters have always had a fascination with the Double Rifle. Actually owning one was the childhood dream of many a poor farm boy. I actually realized that dream in the 1950s, albeit a short-lived one since that particular Doppelbuchse was the equivilant of 5 conventional rifles in price and it was soon replaced by a rack full of Winchesters and Remingtons.
In the 1930s, gunsmith and entrepeneuer O.H.Elliot sought to satisfy the demand for double rifles in the United States by importing custom made rifles which he chambered for his own series of Express cartridges. Made from 405 Winchester brass, the series consisted of the .277, .303, and 357 Calibers.
World War II put a halt to his venture and it was never resurrected as far as I know. His wildcat cartridges are seldom encountered today and are highly sought after by collectors.