I have a S&W 317. The trigger is probably twice as heavy as my model 15. Yes, it's normal. .22 is a great beginners gun in semi-auto, not in a revolver. The trigger is generally heavier, at the firing pin hit is usually harder. Yes, I've had arguments about this before, but by intent and general nature, rimfire requires a harder hit.
"We have normality. I repeat, we have normality. Anything you still can't cope with is therefore your own problem." Douglas Adams