Any .22 rifle experts here? I need to tear down the bolt of the noted single shot and I cannot find a reference to do so.

Here's a good quick explanation with a couple pics.
Better than I can explain with just words.

You can further disassemble the striker assembly by unscrewing the knurled cocking knob from the striker itself. Note the assembly positions of the rebound collar, mainspring and the washer inside there as you take it apart so reassembly goes w/o issues.

Model 15/120 bolt assembly/disassembly - RimfireCentral.com Forums

Thank you very much!!! It appears that this one has possibly been "Bubba'd" as someone has crudely crimped the firing pin in place.