The vehicle was allegedly displaying false number plates while travelling on the M73 near Gartcosh on Monday evening.
Officers said that when they ordered the Range Rover to pull over, they spotted the weapon in the footwell of the car.
The two male occupants of the car were arrested in connection with multiple alleged offences, including weapons possession, dangerous driving, drug driving, failing to stop and crimes of dishonesty.
They arrested a suspected drunk driver at 5am, as well as a pedestrian who allegedly started to fight with them while walking along the M8 motorway.
