Some forgotten weapons are lost gems, and some are designs that really never should have gotten off the drawing board. The S&W Model 1940 Light Rifle is the latter, and a company with as much history and Smith and Wesson really should have known better.
In a nutshell, the M1940 was a hobbled version of a WWI-era submachine gun; too expensive and not useful enough to justify. It was all milled but crippled by parts breakage; had a 400m micrometer adjustable sight but fired from an open bolt; neatly directed brass away from the shooter but made malfunction clearing impossible in doing so.
As was rather drolly stated in a 1968 Gun Facts magazine article on the M1940:
After 900 to 1,000 rounds, we are told by two very competent sources, the end of the receiver would snap right off. Doubtless this annoyed the British.
You can download the whole article from the Smith & Wesson Model 1940 Light Rifle page in the Vault, as well as read a more detailed history of the gun and download the original S&W manual.
Neal and Jinks have pipe dreams of them all, Mark I’s and Mark II’s alike, sitting in pristine splendor swathed in cosmoline
in a British warehouse. More likely they were heaved into the Channel, which is what the British traditionally do with the tools of their salvation every time they ‘ve won the war to end all wars.