The WWII idea is the Colt Ace as that was the only thing available until into the late 60s. Fred Kart only made his conversion for three or four years during the late 1970s. He was working on a 32S&WLong conversion and I got on his order list in 1977 but the project died with no units released for sale and Fred went through some financial difficulties, moved to the south and took up manufacture of truly excellent match barrels. They still dominate conventional pistol in the US. Kart conversions are highly valued and quite rare in Canada.
Dr Jim