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 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.
This was the briefest cross-examination of the trial so far, says the BBC’s Andrew Harding.
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.
Mr Pistorius said in his statement at the start of the trial that he woke in the early hours and walked on his stumps to the balcony, pulled in two fans, closed the sliding door and drew curtains. He said that shortly before he had spoken to Reeva, who was in bed beside him.
He said he rejected prosecution claims that a witness heard arguing coming from the house before the shooting.
2. Bathroom noise
Mr Pistorius said he heard the bathroom window sliding open and believed that an intruder, or intruders, had entered the bathroom through a window which was not fitted with burglar bars.
“Unbeknown to me, Reeva must have gone to the toilet in the bathroom at the time I brought in the fans,” he said.
Mr Pistorius said he approached the bathroom armed with his firearm, to defend himself and his girlfriend, believing Ms Steenkamp was still in bed.
Both sides agree four bullets were fired. Ms Steenkamp was hit three times.
Mr Pistorius said he fired his weapon after hearing a noise in the toilet which he thought was the intruder coming out of the toilet to attack him and Ms Steenkamp.
He said he was in a fearful state, knowing he was on his stumps and unable to run away or properly defend himself.
Mr Pistorius said he rejected claims that he was on his prostheses when he shot at the door.
A witness told the trial she woke to hear a woman screaming and a man shouting for help. She said that after the screams she heard four shots.
At his bail hearing last year, Mr Pistorius said he went back to the bedroom after shooting at the toilet door, then noticed Ms Steenkamp was not in bed.
Mr Pistorius said he then realised she could have been in the toilet.
5. Toilet door
Mr Pistorius said he went back to the bathroom but the toilet was locked, so he returned to the bedroom, pulled on his prosthetic legs, turned on the lights before bashing in the toilet door with a cricket bat.
Forensics expert Johannes Vermeulen told the court that the height of the marks on the door caused by the cricket bat suggest Mr Pistorius was on his stumps at the time.
6. Emergency calls
Mr Pistorius’s defence team has said he then called security at the gated housing complex and a private paramedic service before carrying Ms Steenkamp downstairs.
But security guard Pieter Baba told the trial he had called Mr Pistorius first, in response to neighbours’ reports of gunfire, and not the other way round.
He said Mr Pistorius had told him: “Everything is fine,” before calling him back a few minutes later and crying down the phone.
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 and Ms Steenkamp – a 29-year-old model, reality TV star and law graduate – had an argument before he fired the shots that killed her.
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.