One of the men was black with a red and white chequered bandana, while the other man was white and was wearing a black bandana, he said.
Mr Carpenter said: "I was walking home from the shop when I saw a black man and a white man walking down the main road and turn into Hindrey Road. After about 30 seconds I heard three loud bangs. It's unnerved me a bit because my family live nearby."
The Aberystwyth University student, whose family has lived in the area since he was 10 months old, said there were known feuds between gangs on rival estates.
"It's not so much a war, more of a feud between the Pembury and Nightingale estates, and another one," he said.
Detectives from Operation Trident, which investigates gang-related crime, are hunting two suspects seen running from the scene. One is black, police said, while the second is light-skinned, possibly of Asian or Turkish appearance.