Ballistic Vest - Rifle Resistant Armor

Rifle Resistant Armor

Because of the limitations of the technology a distinction is made between handgun protection and rifle protection. See NIJ levels 3 and 4 for typical requirements for rifle resistant armor. Broadly rifle resistant armor is of two basic types: ceramic plate-based systems and hard fiber-based laminate systems. Many rifle armor components contain both hard ceramic components and laminated textile materials used together. Various ceramic materials types are in use, however: Aluminum Oxide, Boron Carbide and Silicon Carbide are the most common. The fibers used in these systems are the same as found in soft textile armor. However, for rifle protection high pressure lamination of ultra high molecular weight Polyethylene with a Kraton matrix is the most common.

The Small Arms Protective Insert (SAPI) and the enhanced SAPI plate for the US DOD generally has this form. Because of the use of ceramic plates for rifle protection, these vests are 5–8 times as heavy on an area basis as handgun protection. The weight and stiffness of rifle armor is a major technical challenge. The density, hardness and impact toughness are among the materials properties that are balanced to design these systems. While ceramic materials have some outstanding properties for ballistics they have poor fracture toughness. Failure of ceramic plates by cracking must also be controlled. For this reason many ceramic rifle plates are a composite. The strike face is ceramic with the backface formed of laminated fiber and resin materials. The hardness of the ceramic prevents the penetration of the bullet while the tensile strength of the fiber backing helps prevent tensile failure. Examples of rifle resistant outer vests include the Interceptor body armor and the Improved Outer Tactical Vest.