Underwood Ammo 836Underwood Ammo 836 Xtreme Penetrator 357Mag 140gr Solid Monolithic 20 Per Box/10 Case

Underwood Ammo's 836 Xtreme Penetrator in .357 Magnum pairs precision handloading with Lehigh Defense's solid copper bullet technology. Built on a 140-grain monolithic copper projectile, this round delivers the penetration and barrier-defeating performance serious handgun shooters demand—whether for home defense, duty carry, or field use where deep, reliable penetration matters. Each box contains 20 rounds, with 10-box cases available.

The Xtreme Penetrator's design centers on a purpose-engineered nose geometry that drives penetration without relying on expansion. A solid copper construction eliminates lead, making it cleaner to handle and shoot, and the CNC-machined bullet body features hardened cutting edges designed to push through intermediate barriers—drywall, light barriers, and other obstacles—without deformation or deflection. The blunt nose profile supports reliable feeding in lever-action and semi-automatic platforms while transferring energy early in the wound column.

This is ammunition built for shooters who prioritize deep, straight-line penetration over expansion. The monolithic solid copper construction means no jacket-core separation, no fragmentation, and consistent performance shot to shot. Underwood's handloading pairs consistent brass, proven powders, and quality control with Lehigh's bullet design—a combination that delivers shooters who shoot often appreciate.

Key Features

• Solid monolithic copper construction (lead-free)
• CNC-machined bullet with hardened cutting edges
• Engineered nose geometry for maximum penetration and hydraulic effect
• Blunt nose profile for reliable magazine feeding
• 140-grain bullet weight in .357 Magnum
• 20 rounds per box; 10-box cases available

Specifications

Frequently Asked Questions

Will Xtreme Penetrator ammunition feed reliably in my .357 lever-action or semi-auto?

Yes. The blunt nose profile is specifically designed for reliable magazine and chamber feeding in both lever-action and semi-automatic platforms, unlike many solid copper or non-expanding designs.

What makes solid copper monolithic bullets different from jacketed expanding rounds?

Monolithic solid copper bullets like the Xtreme Penetrator prioritize deep, straight-line penetration and barrier performance over expansion. There's no jacket-core separation, no fragmentation, and the hardened cutting edges are engineered to defeat intermediate barriers without deflection or deformation.

Is this ammunition lead-free?

Yes. The solid copper construction eliminates lead entirely, making it cleaner to handle and shoot.

How many rounds are in a standard purchase?

Underwood Ammo 836 Xtreme Penetrator is packaged 20 rounds per box. Cases contain 10 boxes (200 rounds total).