Victim who wore helmet to bed bought gun

A home-invasion victim who became so scared he sometimes wore a motorcycle helmet to bed has been spared jail for illegally possessing a gun he bought for protection.

Robert John Wagenknecht was left with a fractured skull and multiple knife lacerations in May 2013 when three men invaded his Smithfield home in Adelaide.

Judge Paul Muscat said Wagenknecht bought the Ruger .357 calibre revolver for $2000 to provide himself with a sense of security.

"I also note from the file that there were times when you would wear body armour to bed and occasionally sleep with a motorcycle helmet on, such was your fear of being invaded and attacked again," he said.

Wagenknecht, 56, pleaded guilty in the District Court to possessing a firearm while not licenced in March 2014, a handgun police found in a concealed space above a cupboard in his hallway.

Judge Muscat last week suspended a four-month jail term, placed him on a 12-month good behaviour bond and banned him from holding a firearms licence for four years.

He also advised him to move, saying he could not imagine living with such fear.

Wagenknecht, who was asleep when the men invaded his home, was attacked with a knife from his own collection.

"You were able to extricate yourself from your attackers because you produced another knife which you used to attack and wound one of the home invaders with," the judge said.

A DNA match to blood left at the scene resulted in a man being charged over the attack, but a warrant was issued for his arrest when he failed to appear in court.

The judge said Wagenknecht was naturally fearful the man might come after him, noting his home was again invaded in December 2013, but he was out.

"Things were not made any easier when you were visited by two bikie gangs telling you that you required protection and seeking money from you in order to provide you with that protection."

Although Wagenknecht believed the state could not guarantee his safety, the judge said there was no constitutional right to bear arms.

"You simply cannot break the law in order to make yourself feel safe."