3-Nitro-1,2,4-triazol-5-one (NTO) is a promising candidate of insensitive munitions and it is currently explored to achieve shock insensitive melt-cast formulations. Rheology of melt-cast formulations helps in implementing viscous behaviour to application. In the present study, NTO based melt-cast formulations are prepared using TNT as a dispersant and the flow behaviour of non-spherical and spherical NTO formulations are studied along with the bench-mark Composition B. All measurements are made at 81, 83, 86 and 90 degrees C and at shear rates varying from 8.5 to 59.5 s(-1). Flow behaviour of these formulations at process temperatures exhibit non-Newtonian behaviour with yield stress. Time and temperature dependency of these formulations are also studied and about two fold increase in thixotropic index is observed in RDX/I'NT in comparison to spherical NTO/INT (60:40). In order to get more insight on the flow properties, molecular-orbital calculations were performed at B3LYP 6-311G (d, p) level. The calculated interaction energies revealed that stronger attractive forces exist in NTO-NTO than RDX-RDX pairs and similarly in NTO-TNT than RDX-TNT. Correlation with particle morphology confirms domination of morphology over intra/intermolecular interactive forces in determining the yield value. This comparative study establishes the role of above interactive forces and morphology on pourability of melt-cast formulations and further reveals that the flow behaviour of NTO based formulations is superior to RDX/MIT formulations. (C )2014 Elsevier B.V. All rights reserved.