From Longman Dictionary of Contemporary Englishput/hold a gun to somebody’s headput/hold a gun to somebody’s heada) to put a gun very close to someone’s head to shoot them or to force them to do something He put a gun to her head and told the cashier to hand over the money. b) to force someone to do something they do not want to do You chose to live here. Nobody put a gun to your head. → gun
Examples from the Corpusput/hold a gun to somebody’s head• He might as well have put a gun to my head.