My pops is looking to get a new 22LR for dealing with backyard varmints that have been "terrorizing" laugh the pond he built. He's got a Mark II but would rather not have an autoloader since he'll be using low powered ammo. He's been looking at the Ruger Single Six Hunter (integral scope rail); its a cool gun, but a little expensive for his purposes, I think. I suggested a 22 repeater rifle like the Henry, figuring it'll make for more accurate extermination, at a lower price, and he can still mount a red dot or low powered scope (his vision isn't as compatible with iron sights as it used to be). I told him that I though the subsonic ammo would be quieter in the rifle than the pistol, but when he pressed me, I realized I had no basis for that notion. Am I right? And if so, why is it quieter out of a rifle? Also any gun suggestions are welcomed.