TL;DR: The Core Truth of Home Ballistics In a home defense scenario, **Concealment** (hiding from view) is NOT **Cover** (stopping a projectile). Most residential building materials (drywall, plywood, hollow-core doors) offer zero ballistic protection against modern defensive rounds. **Hard Cover** requires high-density materials (concrete, masonry, structural steel, or Earth-fill) that can dissipate the kinetic energy of a bullet. Survival depends on understanding the "Fatal