Demand to carry revolver denied (7)
I believe the answer is:
negated
'denied' is the definition.
(I've seen this before)
'demand to carry revolver' is the wordplay.
'demand' becomes 'need' (synonyms).
'to carry' means one lot of letters goes inside another.
'revolver' becomes 'gat' (I've seen this before).
'need' placed around 'gat' is 'NEGATED'.
(Other definitions for negated that I've seen before include "Nullified" , "Abrogated" , "Denied" , "Discredited" , "Made ineffective" .)