The successful establishment of civil supersonic transport relies heavily on reducing sonic boom signatures to an extent that will enable overland flights. To this end, the Gulfstream Aerospace Corporation has developed a point-design plug nozzle concept with an extended shroud aimed at maintaining low boom characteristics during supersonic cruise. To investigate the aerodynamic and performance characteristics of this nozzle type, a subscale plug nozzle model has been designed, fabricated, and tested throughout the expected envelope of nozzle pressure ratios (NPRs) – roughly 1.4 (takeoff) to 6.2 (design). Tests were conducted at Purdue University's Zucrow Laboratories using a coannular, static, vitiated nozzle test rig capable of simulating typical turbofan exit conditions. Steady and dynamic surface pressures were measured, vibration data was captured, and high-speed schlieren and shadowgraph imaging were incorporated to obtain a more complete picture of the nozzle behavior. Steady-state pressure data were combined to show pressure distributions for given NPRs, while the power spectra were extracted from the dynamic measurements to show dominant fluctuation frequencies. The use of glass as a shroud material allowed shadowgraph visualization of the internal flow structure, which proved extremely valuable in enhancing the understanding of flow behavior at low NPR. Results verify good performance at the design condition but also show highly unsteady flow at low NPRs dominated by boundary layer and separation characteristics along the plug. Variable geometry will most likely be necessary in order to implement this design in a production system.