to switch to bolt action these are the parts needed
breech with old screw location steel , aluminum, brass, plastic your choice.
a new style barrel length optional. if going with a longer than stock barrel you can either free float the barrel ( no accuracy issues ) ream the stock barrel band or get an after market barrel band. caliber optional ( .177/ .22 ) and bolt to match stock, brass, aluminum, steel, extended probe or hollow probe
new style transfer port. if you have the transfer port with one long side and one short side then you will want to switch to the new style which is equal on both sides reducing or eliminating any leaks at that point.
another great option is a stainless steel slotted or Philips 4-48 screw. sure beats the heck out of the stock allen key screw.
I believe that covers converting the upper into the new style