in the gun

in the gun

slang Drunk. Do you remember last night at the bar at all? You were really in the gun.
See also: gun
Farlex Dictionary of Idioms.

in the gun

mod. alcohol intoxicated. (see also shot.) When Fred is in the gun, he’s mean.
See also: gun
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • pull a gun
  • pull a gun on (one)
  • gun-shy
  • hold a gun to (one's) head
  • hold a gun to head
  • hold a gun to someone's head
  • hold/put a gun to somebody's head
  • put a gun to (one's) head
  • Quaker gun
  • have a gun to your head
References in classic literature
In any case, it was decided in the Gun Club that Blomsberry brothers, Bilsby, and Major Elphinstone should go straight to San Francisco, and consult as to the means of raising the projectile from the depths of the ocean.
Weapons produced in the Gun Quarter could be found on the battlefields, not just of the two World Wars, but also the Napoleonic Wars and even the American Civil War.