Piece of cast metal pub reportedly obtained (5)
I believe the answer is:
ingot
'piece of cast metal' is the definition.
(I've seen this before)
'pub reportedly obtained' is the wordplay.
'pub' becomes 'inn' (an inn is a type of pub).
'reportedly' shows a homophone (sound like).
'obtained' becomes 'got' ('get' can be a synonym of 'obtain').
'inn' is a homophone of 'in'.
'in'+'got'='INGOT'
(Other definitions for ingot that I've seen before include "Precious metal bar" , "Mass of precious metal" , "Block of precious metal" , "Lump of gold etc" , "Bar of cast metal" .)