Bolt Removal Harrison and Richardson Model 351 Huntsman 12 Gauge

[The Hermit]

I'm trying to clean up and restore a Harrison and Richardson Model 351 Huntsman for a friend. The action won't cycle and was really stuck. I got it moving now but it won't close and I can't get the bolt out. Might you have any tips on how to remove the bolt? Do I need to disassemble the trigger? Or?

 

[Brutus]

From my meager research online, something about backing off a large screw left hand side of receiver.
Could be covered by seemingly a plastic piece.

 

[Brutus]

I am double guessing this two way discussion amongst others inferred the barreled action firstly removed from the stock ???

maybe....