Developments of tank gun recoil system have led to the design of new concentric hydro-spring recoil mechanisms for the purpose of compactness and high;performance. This new recoil mechanism is used in the modern high power tank guns. This work is intended for the analysiS of the function. as well as the determination of the performance of this new system. A mathematical model is established for the calculation of the recoil paramet6rs of this new system. Another mathematical model is established for the classical recoil system. Experimental measurements are performed during actual firing to validate the mathematical model. A comparison is held between the recoil parameters of two tank guns, the first is equipped with the new hydro-spring recoil mechanism, whereas the second uses the classical recoil system.