Do you mean a Ruger .22 pistol, like my old Standard Model?
The trick to reassembly is to flip it upside down when remounting the grip to the receiver. The little do-hicky deal that has to fit into the spring has to wiggle back and hang free to find the spring hole. I kid you not. Once you get the hang of the upside-down do-hicky hang, it’s a snap. Really.
Negative, this one. It is essentially a 10/22. I found putting the bolt and charging handle back in was tricky, also re-attaching the upper to the lower was tricky because the hammer became detached from its spring during disassembly.
ROFL!!!!
THAT, friends and neighbours, is the voice of experience. The description applies to the "Ruger Standard Model" and "Ruger Mk. II" (at least) .22 pistols. I have yet to meet anybody who knows how to field strip the bloody thing, who can describe the re-assembly procedure without using a word like "doohickey" or "dingbat".