The growth of unmanned systems deployment in the U.S. military has created an even higher demand for human-robot interaction (HRI) research. Currently, unmanned systems implemented for military operations are non-autonomous and require collaboration with human teammates. In order to optimize the effectiveness of human-robot collaboration, it is important to consider the implications of introducing an unmanned system into team interactions. This paper summarizes the methodology and results of an experiment to investigate the use of a Remote Weapons System (RWS) in place of a human Fire Team member and its impact on teamwork quality and trust in unmanned systems. 144 U.S. novice and expert Army soldiers were divided into 4-person Fire Teams and performed simulated missions. Teams were either fully manned or consisted of three human members and one RWS. The results suggested that teamwork quality improved significantly within both novice and expert Fire Teams when the teams included the RWS. Trust in unmanned systems also improved among novice teams; however, there was no significant change in human-robot trust among experienced soldiers.