1
general::
Phrase(s): under the gun (about something)
Go to under pressure.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Under pressure to solve a problem or meet a deadline, as in The reporter was under the gun for that article on taxes. This idiom alludes to a gun being pointed at a person to force him or her to act. [Colloquial; c. 1900]
American Heritage Idioms