I could be wrong, have been before and if I live a day or two more, will likely be again.
However, to my knowledge, RUGER has never made a true controlled feed rifle, Controlled being in this case, rifle which can ONLY be loaded from the mag.
Now maybe they did so for the rifles possibly making trips to Africa, but I have had #77s of one kind and another since early in RUGER's centerfire production and have never owned a true controlled feed RUGER.
I just looked at my years old production "Flat Bolt" RUGER 77 - .243 and while it has the full length extractor, it is push feed, and can not pick up a cartridge from the mag., behind the claw extractor. It is ONLY and ALWAYS a push feed.
My much more recent Hawkeye 300 Win. Mag., is a "controlled feed" in that it will load and control a cartridge from the mag..
But even that is not is a "true controlled feed" as you can drop a loaded round on the follower and the bolt would PUSH the cartridge into the chamber at which time the extractor will snap over the rim of the cartridge, something which a true controlled feed rifle will not do in it's orig. configeration.
In those rifles, the cartridge must come up from the mag. and the rim must be behind the claw of the extractor as it comes up from the mag.
Yes, my Hawkeye will do that, but it will also allow a cartridge to be single fed and chambered without being pushed down into the mag.
Much if not all of the reason for the true controlled feed was military considerations, making it impossible for a single fed cartridge to cause a "jam" with 2 cartridges as the bolt's forward travel automaticaly picked up a cartridge from the mag. during it's forward travel.
Keep em coming!
Crusty Deary Ol'Coot