Abstract: An automatic tissue sampling device includes a housing having an upper opening and a cover closable over the opening. A biopsy needle assembly is operatively disposed within the device, and includes an outer cannula and an inner stylet. A drive mechanism includes a cannula carriage and a stylet carriage slidably disposed within the housing and a system of springs for driving the first and second carriages to pierce a tissue site and obtain a tissue sample. The cannula and stylet of the needle assembly are each supported on the respective carriages by corresponding hubs. The hubs are configured to be received within the carriages to impart driving motion from the carriages to the needle assembly. In one aspect of the invention, the hubs each include a flag attached to the hub and projecting laterally away from the longitudinal axis of the hub. Each flag is sized to be manually grasped to install or remove the hubs from the carriages.