Great job JP ! ...
This is a circuit that will detect metals for sure ! (Btw, does it belongs to this forum ?

)
Anyway i am sure this is a good schematic to build a working pistol detector.
At a later point one could upgrade it with an electrostatic detector connected anywhere on one of the coils and make it a perfect LRL project.
(I hope mesy something transfered the right amount to your account)
No one can claim anymore " i could not find a complete schematic on the forum" !