22 rimfire ammo was originally black powder. It meant your rifle was to be used with Smokeless ammo with lubed bullets instead of black powder cartridges. I think most if not all factory 22 ammo is lubed or waxed. Some more so than others. They just don't put greased or smokeless on the boxes anymore.
"Onward up many a frightening creek, though your arms may get sore and your sneakers may leak. Oh! The places you'll go!" ~ Dr. Seuss