Officers were called at 4.25pm to Richmond St, Forbury following "suspicious behaviour" in a vehicle.
A police spokeswoman said a ute was parked in a driveway with what was reported to be a weapon.
It is understood it was thought to be a gun, she said.
There was mention of the people involved dismantling the device at one point, she said.
It was later confirmed to be a paintball gun.
Police were making enquiries.
Officers were seen after the callout speaking to several men outside the Mobil service station on Hillside Rd.