Ivan D’Angelo told a Supreme Court jury on Thursday how he would wake up with a ‘‘brekkie bong’’ and then start drinking and smoking marijuana for the rest of the day until he went to bed.

The only thing he had to eat during the day before the shooting was two slices of pizza, at about 8.30pm.

Defence barrister Peter Faris, QC, provided the jury with a chart detailing Mr D’Angelo’s drinking and drug-taking habits.

Asked how he was able to carry out skilled panel work when drinking so much beer, Mr D’Angelo replied: ‘‘Pretty much before I even started my apprenticeship, my brother's friend was teaching me how to panel beat and I've learnt to drink while I work, it's a normal thing for me.

‘‘I'm immune to it, that's what I do pretty much every day.

‘‘I've been smoking marijuana since I was 15 years old, drinking alcohol pretty much from the same, probably about 17, something like that, and I've been pretty heavy right from the start.’’

Mr D’Angelo, 39, pleaded not guilty to murdering Wade Vandenberg, who died from a single .22 bullet wound to the head in the early hours of March 28 last year, when he and two other men were aiming to gain entry to the yard outside the factory.

Mr D’Angelo pleaded guilty to the alternative lesser charge of manslaughter, claiming Mr Vandenberg’s death was an accident.

Mr D'Angelo had been living in an upstairs area of his panel beating business when he heard a noise just after 2am, took a gun with a telescopic sight from a safe and fired one shot from an upstairs window.

Crown prosecutor Anne Hassan told the jury Mr D’Angelo was guilty of murder because he "lined up the deceased man's head" and fired with the intention of killing or seriously injuring him.

Ms Hassan said Mr Vandenberg, 26, was standing next to a man with boltcutters in the rain when a shot was was fired "out of the dark" and without warning.

Mr D’Angelo told the jury on Thursday how he heard a dog barking next door and got up and saw three men in front of the factory gate.

‘‘I heard the gates moving so you could actually hear a lot of noise, so I knew they were doing something to the gate,’’ he said.

‘‘To be honest I didn't know what their intentions were, if they were there for the cars or to come into the shop, I'm not sure.

‘‘When I seen them at the gate, hearing the gate that's what scared me, believing they might actually come in to hurt me, something like that ... hurt me, kill me, who knows.

‘‘When I seen them there I went and put the light on and that's when I grabbed my firearm out of the safe.’’

Mr D’Angelo claimed he poked the gun out the window not realising it was loaded.

‘‘I was hoping to get the attention of the three guys, hopefully they will see the light coming out from the window and see me standing at the window.’’

He screamed ‘‘hey’’ to the men as loud as he could, when the gun suddenly went off.

‘‘I was shocked it actually went off, yes, I believed it wasn't loaded.’’

Mr D’Angelo said he saw Mr Vandenberg’s knees ‘‘sort of buckle like that and then he has just fallen straight on his back’’.

The jury found Mr D’Angelo not guilty of murder on Thursday afternoon before he formally pleaded guilty to manslaughter.

Justice Lex Lasry remanded Mr D’Angelo to appear on October 7 for a pre-sentence hearing.