John Shields, 28, had a death wish and had gone into the club at Mytholmroyd for a drink to give himself some "Dutch courage" in order to carry out his morbid plan, Calderdale magistrates heard.
But the starting pistol accidentally went off and shocked staff alerted police.
The court heard Shields had intended to break into a car and create a scene by waving the fake weapon around in the hope that armed response officers would shoot him.
Jane Farrar, prosecuting, said: "He wanted to commit suicide."
Shields, of School Street, Greetland, who admitted possessing an imitation firearm and possessing cannabis, was pointed out by members of staff when police arrived. He had a balaclava, a ski mask, gloves, hats and a crow bar along with the pistol and cannabis in a bag.
He said if the alcohol had not given him the courage to go through with the death wish plot he had intended to eat the cannabis to "numb" himself.
Mrs Farrar said: "The revolver was a blank firing starting pistol."
Larry Parks, for Shields, said his client suffered from bouts of depression.
Shields tested positive for cocaine.
Mrs Farrar said Shields has previous convictions for wounding with intent, burglary, theft, threatening behaviour and possessing a class B drug.
Sentencing was adjourned until July 14 and Shields was remanded in custody.
As reported by the Courier, police were called to the club on Saturday night.
A member of staff reported seeing a man with a gun.
Peter Copley, club steward, said: "The police arrived in no time at all."
A woman who lives nearby said she had heard a commotion and saw a police car parked outside.
"They had someone in handcuffs and were searching his bag," she said.