This presentation will describe the spall evolution and failure mechanisms in 3D printed Stainless Steel 316L (SS316L) fabricated through Powder Bed Fusion (PBF). The PBF fabrication process yields a microstructure which may consist of columnar grains aligned along the build direction, dendritic chemical segregation, sub-granular cellular defects, precipitates, orientation/ texture preference, and some amount of inherent porosity. Spall failure is driven by the interaction between defect structures and grain orientations relative to shock wave propagation. Thus, the spall properties and failure responses of PBF SS316L vary based on the process parameters and resulting microstructures. PBF manufactured cylinders were impacted using an 80-mm gas gun at pressures ranging from 2.92 GPa to 7.03 GPa in order to generate varying levels of incipient to near complete spall failure. The target fixture employs two samples. One instrumented sample backed with PDV and VISAR probes to capture free surface velocity profiles. The other sample is soft recovered in the catch tank for postmortem microstructure characterization. Electron Backscatter Diffraction (EBSD) in combination with Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and image analysis is used to determine the role of PBF microstructure and processing defects on spall initiation and propagation. Effects of heterogeneous microstructural defects including voids, melt pool lines, and texture preferences, as contributing to initiation of dynamic tensile and spall failure will be discussed.