Underwood Xtreme Defender 40 S&W Ammo 100 Grain Lehigh Xtreme Defense Fluted Lead Free Box of 20

Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.

The Underwood Xtreme Defender 40 S&W 100 grain load pairs velocity with engineering. Built around Lehigh’s Xtreme Defense fluted solid copper bullet, this lead-free self-defense round launches at 1500 feet per second and delivers 500 foot-pounds of muzzle energy. The machined flutes create radial hydraulic pressure that expands the permanent wound cavity to diameters exceeding traditional hollow points — without relying on petal expansion that barriers often defeat. For concealed carriers running compact 40 S&W pistols, this load offers barrier-blind performance with reduced recoil compared to heavier bullet weights.

Performance at a Glance

Underwood manufactures this ammunition in the United States using flash-suppressed powder and nickel-plated brass cases processed with Ducta-Bright 7a technology. The nickel plating improves feeding, resists tarnish during storage, and simplifies reloading cleanup without embrittling the case wall — even under +P pressures. Boxer primers and reloadable cases let you reclaim your brass. The solid copper construction meets lead-free compliance requirements in restricted jurisdictions and eliminates fragmentation concerns when shooting through intermediate barriers like automotive glass or wallboard.

The fluted nose profile forces hydraulic energy inward during tissue penetration, building pressure that creates a permanent wound cavity exceeding 100% of the diameter produced by expanding hollow points — while maintaining penetration depths up to 18 inches in calibrated gelatin. When you need defensive performance that ignores intermediate barriers, this 40 cal ammo delivers consistent terminal effect regardless of what the projectile encounters before reaching the target.