An analysis for the transient axial response of a gun launched motor case with unbonded propellant is performed. The present effort extends a previous work by including higher harmonics in the representation of the breech force at the aft end of the motor case. Including the higher harmonics leads to a more accurate representation of the actual breech force. The results of the analysis indicate that the dynamic effects on the internal axial force in the case are negligible for a breech force duration of 0.026 seconds. This is the same conclusion that was made in the previous work based upon a simple representation of the breech force. (Author)