Not rifle related but when you said pocket watch it reminded me of the time I took the cap off the top of one of the injectors in my fiat van whilst trying to fix a fault with it... Holly crap I've never shrunk in confidence so fast . As you say.. billions of really small parts and as Tinbum puts it, there's always "f*** it" spring that pings off with atleast one or more other tiny parts which you never had chance to see how they fitted. The engineer who spent a day and eventually fixed it said very politely to me "don't do that again Rhys will you"
Rhys