BudsGunShop.com - sight fitting

Ove not seen any Piccitany rails for a SR22, and this mounts to pic rail or a weaver rail.
So unless you could find one of those that will fit your pistol it will not.
You could always go with a dovetail mount
https://gallowayprecision.com/optic-mount-plate-for-ruger-sr22-pistols
That will work with the following optics
You have the choice to mount either a JPoint, Shield Sight Reflex Mini Sight, Vortex Viper, Vortex Venom, ADE RD3, Docter/Noblex Sight C, Docter/Noblex sight 2+, Docter/Noblex sight III, Docter/Noblex QUICKsight 5.0 VR, Noblex Sight G, Burris Fastfire 2, Burris Fastfire 3, Delta Optical MiniDot, Delta Optical MiniDot II, Hawke Reflex 1×25, Sightmark Mini Shot Pro Spec, Sightmark Mini Shot M-Spec, Leica Tempus, MAKdot 1×25, or Vomz Pilad 1×20.

Jim, as configured this sight has a Picatinny Mount for a Picatinny top rail. You would need this mounting plate / Reflex Sight : opticsfactory.com/red-dot-sight-for-ruger/RD3-015-SR22