The rapid advance of computer technology and advances in image generation and projection have provided unprecedented growth in the fidelity of hardware-in-the-loop (HITL) simulation. HITL simulation has improved to a level where it can support operational test and evaluation, often providing better insight into system performance than traditional open-air flight tests. This comes at a time of increasing open-air test costs and decreasing test budgets, two factors that are driving the movement for simulation based acquisition. We present two case studies on the application of HITL simulation to the operational test of the AGM-65 Maverick missile system. These studies demonstrate the fidelity of modem HITL simulation, highlight the benefits derived from this testing, and examine the cultural and technical impediments hindering the wider acceptance of simulation based acquisition efforts.