I've had this rifle in storage for maybe four years, never fired. Took it out to shoot, and got a click.

The bolt doesn't sound right when charging. It sounds like a smaller surface is making contact ("clack") instead of the whole bolt face ("thunk").

No discernible strike on rim. Firing pin appears to be protruding adequately when viewed through the open trunnion (I can feel spring resistance when pressing the firing pin with a punch).

My guess is that the bolt isn't going into battery due to improper depth of the barrel. I don't know much about these rifles, though. Just feels like it to me.

Rounds are also not feeding perfectly from a factory mag, and want to stick to the extractor during manual cycling. I initially chalked this up to disuse / break-in, however.

I can't find anything from a web search. Anyone else heard of this?

Look at  manual HERE

Mainly This part:

Barrel Assembly InstructionsThe RUGER®10/22 TAKEDOWN®rifle has an adjustable lock-upmechanism. The following directions describe the adjustment necessary to ensure proper lockup the first time the barrel is installed.

This is it. Thank you.