CONSTABLE Ian Blake was most likely in a weakened state when he shot Nicholas Whiteley at point-blank range in November 2010.
The inquest into Mr Whiteley's death also heard how the 147-gram hollow-point bullet travelled through the 21-year- old's body, and how the crime scene was possibly contaminated in the aftermath of the fatal shooting.
Four police officers provided evidence to coroner Robert Pearce during day four of the inquest, bringing the total police witnesses to 11 officers and one former officer in two days.
Constable Blake had attended Mr Whiteley's Westbury home that Sunday at the request of Mr Whiteley's former partner, who was collecting her possessions after the breakdown of their five- year relationship.
Mr Whiteley and Constable Blake became involved in an altercation during the morning, which ended in Mr Whiteley's shooting and death.
Sergeant Gerard Dutton of police forensics services described the proximity test he had conducted in the aftermath of the incident.
Sergeant Dutton said the test showed that Constable Blake had discharged his Glock 17 pistol within 50 to 120 centimetres of Mr Whiteley, and that the bullet had entered Mr Whiteley's body 15 centimetres above and to left of his belly button.
Sergeant Dutton said that the weapon jammed after the shot was fired, most likely due to Constable Blake being in a weakened state.
The final location of the shell casing also came under scrutiny.
After an initially unsuccessful search, an officer chanced upon the shell outside the back door eight hours after the shot was fired.
Sergeant Dutton said that the most likely explanation for the shell's location was because the scene had been contaminated inadvertently by the movements of Mr Whiteley or Constable Blake after the shot was fired.
Constable Roderick Warrington, operational skills trainer at the Tasmanian Police Academy at Rokeby, also informed the inquest that Constable Blake had deployed OC spray on 21 occasions during his duties between 2000 and 2010, not including on the day of the shooting.
Constable Warrington confirmed that there was only one officer in Tasmania who had used spray more times over that period.
Despite these statistics, Constable Warrington said that he had no cause for concern for Constable Blake's capabilities.
"The numbers are indicative of a man who works," Constable Warrington said.
Constable Blake is expected to give evidence today.