Vertex Solutions, under contract with the Combating Terrorism Technical Support Office (CTTSO), recently delivered an immersive AC-130 virtual reality part task trainer (vrPTT) for use by the Air Force Special Operations Command (AFSOC). The vrPTT provides checklist instruction and practice to AC-130U copilots through the use of an immersive 3D virtual reality (VR) cockpit combined with an intelligent tutor to guide students through 16 copilot checklists and track performance. Key to its delivery, the research team facilitated a verification, validation, and accreditation (VV&A) to confirm that the system met the training requirements for inclusion in the AFSOC 19th SOS Syllabus of Instruction for the AC-130U Mission Qualification Course. Additionally, we conducted a formative evaluation to measure training effectiveness and to inform final refinements to the system. The evaluation participants were AC-130U instructor subject matter experts, current squadron copilots, and current copilot students. The evaluation data included observation of participants using the system, written usability and confidence self-assessment surveys, and individual performance data collected by the intelligent tutor. The results of the evaluation can inform the design and development of future VR training systems. Participants found the system easy to use and 100% believed that the vrPTT would positively supplement existing training to increase confidence and proficiency prior to entering the full motion simulator. Data also indicate the importance of scaffolding within the VR environment to assist with task completion. While the evaluation confirmed many benefits of VR training, it also identified a number of limitations, with most centered on the relative lack of VR hardware/software maturity. Given that technology matures quickly and the identified limitations did not surround the design or implementation of a VR system, we are confident that VR training systems can be a viable time- and cost-saving training option for the military.