A vest made of 15 layers of Kevlar with no steel plates could stop all but which of the following rounds?

Correct Answer: Rifle rounds

Explanation:

Kevlar is a high-strength synthetic fiber used in soft body armor. Soft armor composed of multiple layers of Kevlar (such as 15 layers) is effective at catching and deforming relatively slow-moving or low-energy projectiles by spreading their impact force over a wide area.

Here is a breakdown of how Kevlar interacts with different types of ammunition:

1. Handgun rounds & Shotgun pellets: Soft Kevlar body armor without hard armor plates is specifically designed to stop standard handgun bullets (such as 9mm or .44 Magnum) and shotgun lead pellets, as their velocity and projectile geometry allow the woven fibers to absorb their kinetic energy.

2. Rifle rounds: Rifle ammunition (such as 5.56×45mm NATO or 7.62×51mm NATO) travels at much higher velocities (often exceeding 2,500 to 3,000 feet per second) and features pointed, armor-piercing or high-velocity profiles. Soft Kevlar armor alone cannot stop rifle rounds; hard armor plates (such as ceramic or steel plates) are required to shatter or disrupt rifle bullets upon impact.

Therefore, a 15-layer Kevlar vest with no steel plates would stop handgun rounds and shotgun pellets, but it could not stop Rifle rounds.