Record items containing explosive (7)
I believe the answer is:
cordite
'explosive' is the definition.
(I know that cordite is a type of explosive compound)
'record items containing' is the wordplay.
'containing' says the answer is hidden in the clue.
'CORDITE' can be found hidden inside 'record items'.
(Other definitions for cordite that I've seen before include "Smokeless explosive used in bullets" , "Type of explosive" , "Explosive propellant" .)