The Oscar Pistorius trial, now in its 11th day, has heard from a firearm specialist who testified the athlete had good knowledge of gun use rules.
Sean Patrick Rens is involved in firearms assessment for licences and met Mr Pistorius in 2012.
Mr Pistorius denies murdering his girlfriend Reeva Steenkamp last year, saying he mistook her for an intruder.
The prosecution says he intentionally shot Ms Steenkamp after an argument at his house on Valentine’s Day 2013.
Mr Pistorius had bought a gun from Mr Rens, a Smith and Wesson 500, the trial heard. He had then ordered four guns from him, two shotguns, a LM6 civilian assault rifle, and two revolvers including a .38 special.
The order was cancelled a month after Ms Steenkamp was killed.
Mr Rens read out a competency questionnaire and examination that Mr Pistorius, a South African Paralympic athlete, had completed before he could be issued with a firearm.
He scored top marks in these tests, which included questions about the rules on when you are legally allowed to shoot intruders.
One question was: There is no security gate between you and the burglars. They are armed and they advance towards you. Can you discharge your firearm because you fear for your life?
Mr Pistorius replied Yes.
The next question was: Explain the legal requirements when using a firearm for private use, to which Mr Pistorius answered: Attack must be against you, it must be unlawful, it must be against persons.
The final question on the importance of target identification elicited this answer from Mr Pistorius: Always know your target and what lies behind.
‘Combat mode’
Mr Rens also relates an incident when Mr Pistorius told him about going into code red, or combat mode, after hearing a noise in the house and thinking there was an intruder in the house.
Mr Pistorius got his gun and cleared the house, Mr Rens said, and when he got to the source, he found it was a tumble drier.
This was the briefest cross-examination of the trial so far, says the BBC’s Andrew Harding, who is in court.
Defence lawyer Barry Roux presumably felt he had done some damage with those quick exchanges, and risked undermining Mr Pistorius’ case by prolonging the cross-examination, our correspondent says.
The next witness is police crime scene photographer Bennie van Staden, whom Mr Roux accuses of failing to label his pictures correctly.
The trial is expected to call on more than 100 witnesses. It had been set to last for three weeks, but looks likely to be extended.
The state is seeking to convince the court that Mr Pistorius deliberately shot Ms Steenkamp – a 29-year-old model, reality TV star and law graduate – following an argument.
There are no juries at trials in South Africa, and his fate will ultimately be decided by the judge, assisted by two assessors.
If found guilty, the 27-year-old – a national sporting hero and double amputee dubbed the blade runner because of the prosthetic limbs he wears to race – could face life imprisonment.
