Beauty queen Baylee Curran told the LA Times Mr Brown had pointed the gun at her face after she had been admiring his friend's jewellery.
Mr Brown came out of his home after a stand-off with police on Tuesday.
The singer has several convictions for violence, including a 2009 assault on his then girlfriend, pop star Rihanna.
Police went to Mr Brown's home following the emergency call early on Tuesday from Ms Curran, who by that time had left the property.