The “E” series is the final evolution of the Winchester 1897, at least as far as internals go. This model saw slightly wider grooves on the receiver ring, which it’s doubtful anyone noticed. What does stand out is that the screws for the cartridge stops, set on either side of the receiver, have been replaced with buttons. These allow the shooter to empty a loaded magazine any time they like.
For many, Winchester’s 1897 became THE pump action shotgun, outselling all others for over a decade and even then remaining competitive with its own replacement: the Model 12. A shortened barrel, “riot gun,” variant fitted with a bayonet lug served in both World Wars. Ultimately manufacture lasted until 1957, with over one million made.