A number of gun propellant compositions based on RDX GAP, TAGN and combinations thereof were formulated an studied with the aim to select the suitable composition for advanced gun ammunition in respect of processability and ballistic performance. Theoretical thermochemical properties of the compositions were computed using a 'THERM' programme and the ballistic performance was evaluated on the basis of closed vessel tests. In addition, sensitivity, thermal characterization, thermal stability and mechanical properties of the compositions were also determined for assessing the suitability for application. A composition containing 28% NC, 45% RDX, 20% TAGN, 6% GAP, 0.7% carbarnite and 0.3% resorcinol was found to provide higher level of force constant at relatively lower flame temperature, reasonably good burning rate characteristics and mechanical properties.