Underwood - Xtreme Penetrator - 140 Grain 10mm Ammo - 200 Rounds

The jacketed hollow point is effective, but it does have what you could call “design defects.” Its core and jacket can separate during penetration of a barrier or the threat, thus limiting its penetration depth. Its nose cavity can also jam up with debris, which robs it of its ability to expand.

This 10mm round by Underwood is loaded with a 140 grain Xtreme Penetrator – a solid copper (i.e. lead-free) bullet designed to do away with both of the JHP’s major shortcomings. The Xtreme Penetrator is monolithic and durable, and avoids deflection and fragmentation as a result. Its smooth-feeding nose profile is blunt to promote higher energy transfer and deeper penetration (up to double the depth of a traditional JHP). Instead of expanding to inflict a wide wound channel, the Xtreme Penetrator’s grooved surface creates hydraulic pressure that blasts soft tissues away in lateral directions at high velocities.

If fate forces you to defend yourself in the dark, then you’ll be glad Underwood had the foresight to load flash-reduced propellant. And thanks to this ammo’s smooth-cycling nickel-plated brass cases, it has enhanced resistance against corrosion as well.