Police are appealing for information on the incident, which occurred on the O'Neill Road on Saturday evening.
"Shortly after 10pm, it was reported that two men exited commercial premises on the O'Neill Road and saw two males looking inside the van they had been travelling in," said Detective Sergeant Erskine of the PSNI.
"When challenged, one of the males ran towards one of the men and demanded the keys to the vehicle.
"When the man refused to give him them, the suspect pointed a handgun in his face, before striking him on the top of the head with the weapon, and taking the keys from him.
"Both suspects then made off in the van.
"The man armed with the handgun is described as being approximately 6ft in height, of athletic build and dressed in dark-coloured clothing and balaclava."
Anyone who saw what happened, or who has any information that might assist detectives, is asked to call 101, quoting reference number 1630 of June 14.
