One thought...
Placing a round in the chamber and dropping the bolt on it can damage some rifles. I don't know about the Ruger, but doing so with certain firearms can damage the extractor. It's meant to have the cartridge ride up under the extractor from below... when you chamber a round and drop the bolt, the extractor has to flex out and around the rim. Most are not designed to do so.
You should be able to load your .22 shorts from a magazine... I know they'll feed from a stock rotary Ruger mag ok.
As above, you'll have to alter the rifle to get it to cycle properly, but it's quite safe.
The revolvers you asked about will be just fine with shorts, or longs (or cb's, rat shot, etc). That's one of the benefits of a revolver (or bolt gun), much less sensitive to ammo, as they don't rely on the recoil impulse or gas to cycle the gun.