Present investigation reports the results of systematic studies on the use of bimodal RDX in low-vulnerability ammunition (LOVA) gun propellants. Several formulations based on bimodal RDX as oxidiser, cellulose acetate as binder, and diocty1 phthalate or triacetin as plasticizer were processed with different proportions of 5 micrometer and 20 micrometer particle size of RDX samples in the range 100:0 to 60:40 ratios. The effect of varying the proportion of fine RDX of the two particle sizes on propellant burning behaviour was found to be quite significant. The study concluded that by using bimodal RDX, it is possible to modify burning behaviour without sacrificing low-vulnerability aspects of LOVA propellants