The bullet almost hit the foot of Kevin Lerena, a boxer and mutual friend of Oscar Pistorius and Reeva Steenkamp.
"I got a huge fright, because the bullet hit the ground just centimetres from my foot ... but it really was just a freak accident," Lerena told Beeld.
He said he had visited the restaurant with a group of friends who included Pistorius and Steenkamp.
"I must emphasise that the gun belonged to one of Pistorius' friends --I'm not going to mention his name. Oscar just wanted to look at the gun, and it sort of snagged on his pants, releasing the safety catch. A shot went off. I wouldn't call him negligent, it was just an accident. He apologised to me for days afterwards," Lerena said.
The restaurant did not report the incident to the police, as Pistorius and Steenkamp were regular customers.
"I went to investigate when I heard the shot, but they all denied it," said Tashas' manager, Jason Loupis.