This is an older (1951) CZ Mauser with the double set trigger system. The striker won't cock properly so I broke the rifle down and found that the (at this point please forgive me as I don't know the proper name for these parts) part that extends through the bottom of the bolt rail and catches on the part that holds the firing pin back was already partially depressed so it couldn't hold the firing pin back securely. Usually just closing the bolt causes the firing pin to snap forward. See the first photo and you can see that the lever coming from the trigger mechanism is contacting the part mentioned earlier and it is already partly depressed.




I found that if I pulled the rear trigger "setting" it prior to opening the bolt the lever dropped down leaving a gap and the bolt would cock and fire normally. See next photo of view with trigger "set."




I gather that the little screw between the triggers is to adjust the rear trigger's contact with the part that engages the bolt but it is backed out all the way in the photo and there is still excessive contact between these parts.

Is there an adjustment I am missing or does this require serious smithing?

These are watch parts doing punch press work. Take it to a knowing gunsmith...there may be more than one issue, seems to me. I'd kind of bet the primary sear (front trigger works that) is stoned a little too light...may a case of wood compressing..I dunno