Travis Scott, a prohibited person to possess a firearm, was at the unit on May 20 with his girlfriend when police forced open the front door to execute a search warrant.

Police had received information Scott was in possession of a firearm after a $37,000 Audi vehicle was stolen at Melton between May 10 and 11, and Scott was seen driving other people around in it 10 days later.

The Ballarat Magistrates Court was told on Thursday Scott was in the bathroom ensuite when police arrived at the unit at 9.45pm on May 20 and he climbed into a manhole.

Police prosecutor Sergeant Aimee Heal said after he was arrested and handcuffed, police located the rifle - with the silencer attached - in a wardrobe but they could not find ammunition.

"The accused is a prohibited person because of his most recent term of imprisonment," Sergeant Heal said.

She said police located the keys to the stolen Audi vehicle in the lounge room, while the luxury vehicle was found parked on the unit's front lawn.

Sergeant Heal said Scott, a methamphetamine addict, had a small deal bag containing the drug in his wallet.

She said earlier this year in January and February, Scott failed two oral fluid tests after police stopped him driving in Haddon and Sebastopol.

On January 3 Scott was clocked driving 115km/h in a 100km/h zone on Carngham Road, Haddon, while unlicensed. He was tested for drug-driving and was found with methamphetamine and MDMA in his system.

Sergeant Heal said on the second occasion on February 8, police saw Scott driving unlicensed in the Sebastopol area.

They approached him at a service station where he was drug-tested and found with methamphetamine in his system.

The court was told Scott breached a family violence intervention order by sending two messages, via a messenger app, to the affected family member after his release from prison in November.

Scott pleaded guilty to several charges via video link at a contested mention on Thursday. They included being a prohibited person possessing a firearm and silencer, unlicensed driving, drug-driving, speeding and breaching a family violence intervention order.

His lawyer said her client was released from jail in November and he had relapsed into drug use, which was an underlying issue that led to his offending.

She said when released from jail, Scott could live with his employer and work with him, or live with a colleague's mother.

Magistrate Alan Spillane said possessing a firearm with a silencer on it was the most serious offending.

Scott was sentenced to six months in jail, with 115 days already served on remand. He was fined $475 and disqualified from driving for two years.