Darko Felding, 50, and Zachary Felding, 20, were arrested late last year after what police said was a bloody altercation in the Gungahlin suburb of Taylor.

In documents tendered to the ACT Magistrates Court, officers said the pair each armed themselves with a cordless nail gun and left their home on McCredie Street about 11pm on November 21.

They allegedly marched down the street to confront about 10 people who were having a party at another house.

When they reached the property in question, Darko Felding allegedly fired a volley of nails towards the house.

One of the host's cousins came outside and pleaded with the 50-year-old to put the nail gun down, according to police, who said this only made matters worse.

"From a distance of approximately two metres, [Darko Felding] raised the nail gun towards [the man] and fired several times at him," police have alleged in court documents.

"One nail struck [the man] in the middle of the forehead, piercing his skin and causing him to bleed."

Police said the nail was embedded in the 40-year-old alleged victim's skin, so he pulled it out and tried to take the nail gun from Darko Felding.

There was then allegedly a short struggle, also involving Zachary Felding, before both sides retreated to their respective houses.

Police officers who attended the scene a short time later reported finding "a large number" of nails, some of which were stained with blood.

They also took photos of the man allegedly shot by Darko Felding.

Officers then went to the Felding home and found the 50-year-old alleged shooter bleeding from his left eyebrow and wearing a torn singlet.

According to court documents, Darko Felding told police there had been an argument earlier in the evening and that he had gone "to sort it out".

When he was informed that he was under arrest for assault, he apparently asked who the victim was.

A police officer replied: "The guy down the road with the nail sticking out of his forehead."

Darko Felding allegedly retorted: "I f---ing hope he's got a nail sticking out of his head. I shot at everyone."

Both Feldings were granted bail when they first appeared in court on November 23.

Their lawyer, Tom Taylor, said on that occasion that there would be "a contest as to the facts".

Mr Taylor told the court the partygoers may have in fact been the aggressors in the incident, suggesting that the revellers had threatened to shoot Darko Felding's wife earlier in the evening.

Darko Felding was initially charged with carrying out an act endangering life, assault occasioning actual bodily harm, and possessing an offensive weapon with intent. He pleaded not guilty at the earliest opportunity.

Zachary Felding, meanwhile, used his second court appearance to formally deny charges of affray and possessing an offensive weapon with intent.

The ACT Magistrates Court heard on Monday that the 20-year-old had since been charged with a second count of affray, assault occasioning actual bodily harm, and aiding and abetting an act endangering life.

Magistrate James Lawton said an affray charge had also now been levelled at Darko Felding.

Mr Taylor said he had not been informed of the new charges, and he would write to prosecutors requesting copies of them.

The matter is due back in court on March 9.