Underwood 10mm Auto Ammo 135 Grain Nosler Sporting Handgun Jacketed Hollow Point Box of 20

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

The Underwood 10mm Auto 135-grain Nosler Sporting Handgun Jacketed Hollow Point delivers 1600 feet per second and 767 foot-pounds of muzzle energy from a 5-inch test barrel — velocity that places it among the fastest factory 10mm defensive loads on the market. Underwood chambers this round in nickel-plated brass cases primed with non-corrosive Boxer primers, and loads flash-suppressed powder to preserve low-light sight picture. The Nosler Sporting Handgun bullet features a tapered copper-alloy jacket over a two-part lead core, engineered to expand reliably across a broad velocity window while maintaining structural integrity through intermediate barriers. This load is intended for self-defense applications where rapid expansion and deep penetration are both required — concealed carry in bear country, trail defense, and duty use where over-penetration is a concern. Each box contains 20 rounds.

Performance at a Glance

Underwood manufactures this load in the United States, using new-production components tested in real-world firearms — Glock 20, 1911 long-slide platforms, and polymer-frame hunting pistols. The 135-grain weight sits at the lighter end of the 10mm Auto spectrum, prioritizing velocity over bullet mass. At 1600 fps, this round generates a sectional density of 0.121, which translates to moderate penetration depth in ballistic gelatin — typically 12 to 15 inches through four layers of denim. The nickel-plated case resists corrosion when carried against leather holsters or in humid environments, and the plating smooths feeding in semi-automatic actions. Flash-suppressed powder reduces muzzle signature in dim conditions, a feature relevant to defensive encounters where follow-up shots depend on unobstructed vision. The load is suppressor-safe, though the supersonic velocity means you will still hear the crack downrange.

The Nosler Sporting Handgun bullet is a two-part lead-core design — the forward section is softer to initiate expansion at the hollow-point cavity, while the rear core is harder to control deformation and resist jacket separation. The tapered jacket is thicker at the base than at the ogive, which helps the bullet mushroom without fragmenting when it strikes bone or heavy clothing. Ballistic coefficient (G1) is 0.093, a figure typical of wide-muzzle defensive bullets that prioritize expansion over downrange efficiency. This is a short-range load — energy drops below 600 ft-lbs by 50 yards — so zero your sights at 25 yards and confirm point of impact with your carry gun before relying on it in the field. Find more high-velocity defensive options in the Underwood 10mm Ammo category.