Abstract: A structural sandwich panel including a structural sheet bonded to two adjacent sheets with a plurality of spaced columnar projections extending perpendicularly from a local face from the sheets. The sectional panel may be interposed in a void of a double-wall ballistic sandwich panel. The panel provides an interconnected interstitial space between layers that may serve as a filler space for the placement of force diffusing material such as ball bearings to deflect and defeat any projectile when used as a ballistic panel in light amour vehicles, water craft, personnel protection and building structure or equipment, but also provides maximized structural rigidity in the length and width direction of a product.