Jonathon Bradley allegedly "lost it" during a row with the woman during which he allegedly pushed her, causing her to fall over at the property, in Kingswinford near Dudley on September 3, 2019.
Prosecuting barrister Mr Ian Ball told Wolverhampton Crown Court that the police were called to the address by a neighbour who overheard a man's voice shout, "I will kill you" and a woman screaming "help me".
Mr Ball said: "The police officers found her with minor injuries. She told them she had been attacked and threatened with a gun.
"She was taken to a police station and in the meantime Jonathon Bradley was taken to Oldbury. Not only did she relay to the that day's events, but also previous events. She acknowledged that alcohol was a factor that she been drinking gin and tonics."
She told the officers following an incident the previous week, she went to stay with relatives and was returning to collect some belongings, but had to scale the fence to get in as the defendant had kept her phone and keys and locked the garden gate.
"It is the crown's case that he rushed outside. He pushed her to the ground. She could see that he had a gun. She'd never seen him with a gun before. She knew he had a military background and that he went hunting sometimes.
"From her description it was a double-barrelled shotgun. He pointed the gun in her face. She thought she was going to be killed.
"To her horror he shouted that has was going to kill her and then kill himself. He asked her if she realised how close he came to killing her. In other words he lost it.
"She was terrified and her screams were overheard."
Mr Ball said the woman suffered injuries to her face, arm and knees in the latest incident and showed the officers images of previous injuries that she accused him of causing.
Giving evidence shotgun owner Matthew Longville told the jury he often went clay shooting with the defendant and that Bradley drove them to the shooting centre with the two guns transported in his car boot. He said he was unaware that one of the guns was missing until the police carried out a check at his home, resulting in his firearms licence being temporarily revoked.
Bradley, 52, of Gower Avenue, Kingswinford, denies three counts of assault occasioning actual bodily harm, one count each of assault by beating, making threats to kill and possession of a firearm with intent to cause fear of violence.
The trial continues.