Nathan John Jones, 31, faced a part-heard hearing in the Launceston Magistrates Court today on allegations of common assault and having breached a family violence order.

Magistrate Tim Hill found Jones guilty of both charges and will sentence him tomorrow at 11.30am.

Mr Hill said the complainant, Jones' former partner, was a truthful witness and the assault had occurred essentially as she had described in her evidence.

The woman had previously told the court that Jones had entered her house through the roof and she took refuge under a table, when he lowered himself to the floor and head-butted and punched her.

Police prosecutor Brett Steele outlined other offences Jones was to be sentenced for, including five breaches of a family violence order.

He said the offences included Jones tailgating the woman on the East Tamar Highway and leaving a gold bullet, with a handwritten note, in her house. 

Jones will also be sentenced for firearms offences, including an occasion where police found a firearm and bullets in his car.

He is already in jail for a Supreme Court matter, in relation to the same complainant.