Mike,
From John Taffin, Big Bore Sixguns, Krause, Iola, Wisconson, 1997:
After a discussion of Pop Eimer's work in the '20's...
"Colt must have been somewhat interested because in 1932, Remington ran some special loads for Colt. The boxes were marked 41 Special. Fred Moore was the factory superintendent at Colt and was interested in producing a new sixgun cartridge with a 210 grain bullet at 900 feet per second. Again, this was 1932. Three different variations on this theme were tried, with the final version chambered in a New Service, achieving 1150 feet per second."
"In these pre magnum days Colt had the cartridge and it had the sixgun to go forward and it shelved the project. The .41 Colt Special had a case length of 1.260 inches, or 1/10 inch longer than the .38 Special or .44 Special case. When the .357 Magnum arrived three years later it would utilize a cartridge case length of 1.290 inches. Colt could have chambered the Colt Single Action Army and the big New Service double action in a powderful .41 three years before the .357 Magnum brought us into the Magnum era. Colt had the ball and fumbled."
Oddly enough Suydam's U.S. Cartridges and their Handguns, an unusually comprehensive work, does not list this cartridge, though it does, show the older 41 S&W.
I don't know whether the bullet used in the .41 Colt Special was 0.386-0.388" diameter, an upgraded .41 Long Colt (D.A.), or whether it was a true .41 Calibre. The .41 Long Colt (D.A., inside lubricated), case length was 1.130, SAAMI maximum, so that the .41 Colt Special was some 0.130" longer.
The Shooting Master was a variant of the New Service Target, itself a variant of the New Service.
Bob