You can dry-fire any .22 RF Ruger has ever made.
You have to dry-fire the Standard Auto pistol to take it apart to clean it.
Many old cheap .22 rimfires had no positive way of stopping the firing pin from hitting the end of the chamber and denting it.
Not so with most all modern designs.
S&W .22 revolvers are one exception, as enough high-speed hammer impacts can eventually break the firing pin.
But it will not harm or dent the chambers either.
Very few if any modern semi-autos have bolt hold-open devices to prevent dry-firing when you run out of ammo in the mag either.
(Ruger 10/22, Marlin Model 60, Browning SA-22, etc.)
They all get dry fired all the time unless you are a most excellent round counter concentrating on counting rounds, instead of the sights!
Would I intentionally dry-fire a modern .22, 10 gazillion times just for the practice?
No.
Would I worry about it every time I lost count and ran dry in the mag tube?
Of course not.
It was designed that way.
rc