Sounds to me like you may have a loose ejector rod. Make sure it's tight, it's likely to tighten in the opposite direction to normal "righty-tighty, lefty-loosey". Other than that, revolver lockups are normally associated with centerfire primers sticking out farther than they should (not an issue with .22LR). Make sure everything is clean under and around the ejector star.
It would appear that keeping the revolver clean and using ammo that functions reliably are the best remedies for this problem.
True for just about any gun, some are more dirt-tolerant than others.