Hi KAG ................... OldYeager here
I've used 22 shotshells some. I don't think they would hurt your Ruger, in fact it might be the ideal shotshell shooter.
What I use for shotshell mostly is an old (very old) 9 shot H&R 922. We have a creek running thru the property and comes in handy on Cottonmouth water moccs. Killed a big one this Summer here. Distance was about 8 or 9 feet downwards. Snake was in water and shot pattern was size of a dinner plate. Right straddling the middle back. First shot did not kill snake but disabled it from swimming. Head was still moving and tongue still flicking. I was afraid the dog would grab it and get bitten, so fired twice more. It was then good and dead.
The story by Virginian above is sad, but I can certainly believe it. I did not think these little tiny shot could do much either. I have a number of bird feeders hanging from the trees around my house. And the squirrels are pesky little raskels. I don't specially want to kill them over some birdseed. So I kept a little Red Ryder BB gun (spring action) handy just to pepper their hides to discourage them from stealing all the birdseed. They come every day to match wits with me. But one day I ran out of BBs, so I pulled out the snakegun (922) and ran outside. The squirrels usually scatter upon hearing the front door open. But that day one just ran about 30 feet up into tree branches and hid. But I spotted him. I firmly thought I'd only pepper his hide. I shot and squirrel jumped srtaight up and fell out of the tree. It hit the ground and sat up (looking a little stunned). I thought 'now little squirrel put uour fanny in gear and git'. Next thing I knew, the squirrel fell over on its side, kicked a couple times and then was stone cold dead. I felt sad for the critter. And was completely surprized at what that shotshell would do.
I'd have to say, those pellets Can kill small animals out to maybe 50 to 60 feet or so. They don't just burn their hide - they go inside.