Derek Hardie attacked Darren McCabe with a bottle then struggled with him while holding the shotgun, a court heard.
Hardie, 36, of pleaded guilty to a firearms offence and two assaults when he appeared at Livingston Sheriff Court yesterday.
He admitted having a shotgun in his possession at Auldhill Avenue and Auldhill Crescent, in Bridgend, West Lothian, without being the holder of a shotgun certificate.
He also admitted striking Mr McCabe on the body with a bottle and assaulting him by brandishing a shotgun at him and struggling with him.
Not guilty pleas to breaking into a house in Bridgend, forcing open a gun cabinet and stealing two shotguns; possessing a firearm with intent to cause Mr McCabe to believe that unlawful violence would be used against him, and threatening to shoot Mr McCabe, were accepted by the Crown.
Samantha Brown, prosecuting, moved for sentence and said Hardie had no previous convictions.
She told the court that an agreed narrative of the incident would be prepared for the court at a later date.
David McLaughlin, defending, said the offences were “out of character” for his client.
He said the father of two had a full-time job and paid maintenance for the upkeep of the children to his ex partner.
Hardie, of Marchwood Crescent, Bathgate, West Lothian, was released on bail until June 25 when he will be sentenced.
Sheriff Martin Edington called for background reports and warned Hardie that despite his lack of previous convictions the charges were “extremely serious”.
He said: “I require to defer sentence for the preparation of community payback order reports to include supervision, unpaid ours of work and a restriction of liberty order assessment.
“You shouldn’t make any form of assumption about the ultimate sentence in relation to this because all sentencing options – including prison – remain open.”