Firearms training academy manager Sean Rens told the court he met the double-amputee runner in 2012 and that Pistorius asked to be provided with a revolver.
Mr Rens said Pistorius was familiar with rules for using guns and had filled out a questionnaire when applying for new permits.
He said Pistorius told him of one occasion when he had feared intruders were in his home and he had drawn a weapon.
He went into "code red" or "combat mode" after hearing a noise in his house but it turned out to be from the tumble dryer, Mr Rens said.
Pistorius had tweeted about the incident in November 2012, saying: "Nothing like getting home to hear the washing machine on and thinking its an intruder to go into full combat recon mode into the pantry!"
The tweet has since been deleted from his Twitter account.
Mr Rens was also asked to read out questions posed to the Paralympian to assess whether he was competent enough to own guns: At the start of the day Ms Steenkamp's mother June - attending for the first time since the opening day - appeared to acknowledge the athlete and spoke to his sister Aimee in the courtroom.
She left court before evidence from police photographer Bennie van Staden, who discussed pictures taken at the scene - including graphic images of Ms Steenkamp's injuries.
The athlete's sister Aimee spoke with June Steenkamp in court
The court was shown photographs of Mr Pistorius' bloodied prosthetic leg and of unexplained damage to the main bedroom door in the house.
Photographs were also taken of blood spots on the bedroom wall, above one of the bedside tables, the court heard.
Pistorius, who won two gold medals at the Paralympics in London in 2012, is charged with premeditated murder.
He is also accused of illegally possessing ammunition, as well as two further counts related to shooting a gun in public in two separate incidents before the killing.
The athlete denies the charges and says he shot Ms Steenkamp, 29, by mistake after mistaking her for an intruder.