Autonomous UnmannedMilitary Vehicles (AUMVs) became part of numerous military combat operations to meet the challenges of modern warfare techniques and strategies. Hence, there is a need to develop an ad hoc network among AUMVs to perform the military tasks collectively within a war field where infrastructure installation is not possible. Therefore, in this paper a novel AUMVs protocol is proposed to develop a Vehicular Ad Hoc Network (VANET) among unmanned Military Vehicles (MVs). The proposed protocol performs cluster based multicast communication among AUMVs by considering real time and dynamic war field scenario. The AUMVs protocol develops stable clusters and becomes adaptable according to the military environment by using a proposed Priority Based Cluster Head Election Scheme (PCHE) during cluster formation which reduces the network overhead and delay. Additionally, the AUMVs protocol achieves high throughput by combining the multicast approach with a cluster based scheme. The simulation results illustrate that the proposed protocol has achieved the goal of stable and efficient communication among unmanned MVs.