Understanding the mechanisms that control shear-dominated failure under dynamic loading is of critical importance to the Army for enabling lightweight armor systems and autonomous platforms. The fundamental chemistry-processing-structure-properties-performance interactions at multiple length scales are poorly understood, however, a full understanding is required to improve armor performance. We have produced three different advanced high strength steels (AHSS) with different combinations of ferrite (α), BCC phase with relatively low strength, and austenite (γ), an FCC phase with the lowest strength but highest ductility and toughness. Each formulation has a different stacking fault energy (SFE), which activates transformation-induced plasticity (TRIP), twinning-induced plasticity (TWIP), or typical slip dominated deformation. TRIP steels have higher strength and ductility due to the stress and/or strain induced volume expanding martensitic transformation of austenite to martensite. A secondary transformation of HCP martensite (ε) can also be involved, whereby austenite undergoes a volume contraction to ε and then undergoes a volume expansion to form α’-martensite. TWIP steels can also have increased strength and ductility, plus very high work hardening rates. In this case, mechanical twins sub-divide austenite grains into nano-scale bands, leading to a Hall-Petch effect on the flow stress. In this presentation, we will present the dynamic mechanical behavior under tension and compression loading and at room and elevated temperatures. Additionally, we will present the microstructural evolution of recovered samples which have been scanned using electron backscatter diffraction (EBSD). This evolution reveals which deformation mechanisms are active under the different dynamic loading conditions. The goals are understand the aforementioned relationships in order to design an AHSS to improve resistance to dynamic shear localization.