In the past, personal body armor was constructed of simple plates of high- strength alloys. However, with the advancement of modern combat and weaponry, particularly armor-piercing ammunition, personal body armor has evolved into more complex and effective metal, ceramic, and composite structures. This paper lays the groundwork for experimental and modeling methods used to understand the effectiveness of new armor designs. Focusing on the first layer of modern body armor, the ”High Impedance” layer. Experiments measuring the change in velocity of bullets passing through aluminum and titanium plates were conducted. These experiments were then replicated through FEA simulation.