[Lanrezac]

22 Rimfire is one of the oldest metallic cartridges, dating back to the 22 Short that Smith & Wesson introduced for its first revolvers in the 1850's. For many years it was loaded with black powder, and for years after that with something called "semi-smokeless".

Although the amount of smoke they made was not an issue, these rounds also produced too much fouling to function properly in a semi-automatic gun. That is why Remington and Winchester both designed special, different 22 Automatic cartridges when they introduced their first semi-auto 22 rifles; it is also why John Browning designed the 25 ACP cartridge for his first vest-pocket sized pistol. That was around 1905.

I think in the 1920's, fully smokeless 22 Short, Long, and Long Rifle ammuntion became available. This made guns like the Colt 22 Woodsman practical, and it made it possible to make semi-auto rifles as well.

This is why your rifle specifies 22 Long Rifle Smokeless; it was apparently made at a time when 22 semi-smokeless might still be encountered, and it would not function well with that. Because companies tended to use roll stamps until they wore out, your gun might have been made as late as 1960 or so; I'm afraid I don't know anything about it specifically.