The invention relates to a bullet-tail full bounce detecting device capable of automatically detecting the full bounce tolerances of the bullet-tail bourrelets of mortar bullets, which is applied to the automatic production lines of mortar bullet assemblies and can overcome and make up the technical shortage and defect that the traditional bullet-tail full bounce detecting device fully relies on manual operation. The device is directly installed on a pipeline frame body, lifts bullet bodies from a pipeline traveling fixture through adopting an automatic lifting mechanism and supports the bullet bodies through a supporting position according to detecting requirements; the device realizes the axial position and radial compression of the bullet bodies through adopting an axial positioning mechanism and a compressing mechanism to prevent the bullet bodies from generating axial and radial pulsation when detecting, thereby ensuring measuring precision; the device drives a driving support wheels of the bullet bodies and drives the bullet bodies to rotate through adopting a driving mechanism; and the device accomplishes the full-bounce detection of the bullet bodies through adopting a detecting mechanism installed on the automatic lifting mechanism. In the whole working process of the detecting device, all actions of lifting, positioning, rotation, detection and the like of the bulletbodies are automatically accomplished, and the bounce value on a dial indicator needs to be read by people.