Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
The Underwood Xtreme Hunter 10mm Auto merges penetration depth with permanent wound cavity diameter in a single hunting-optimized cartridge. Chambered in 10mm Auto and loaded with a 150-grain Lehigh Xtreme Defense fluted projectile, this round achieves 1425 feet per second from a 5-inch test barrel and delivers 677 foot-pounds of energy at the muzzle. The fluted nose channels fluid radially outward, creating a permanent wound channel that exceeds conventional hollow-point expansion without petal fragmentation. Nickel-plated brass resists corrosion in humid blinds and simplifies post-hunt reloading prep.
Built for the Box
Underwood machines the Lehigh Xtreme Defense projectile from solid copper bar stock, cutting six spiral flutes that begin at the nose and taper toward the bearing surface. During tissue penetration, these flutes channel hydraulic pressure outward rather than rearward, producing a permanent cavity diameter larger than the bullet’s caliber while maintaining straight-line tracking through hide, muscle, and bone. The 150-grain weight balances velocity retention with recoil impulse in full-size 10mm pistols and carbines. Flash-suppressed powder preserves low-light vision if you fire at dawn or dusk. Boxer primers seat in nickel-plated cases that feed reliably in 1911, Glock, and Springfield XD-M chambers and accept standard large-pistol primers during reload cycles.
Load Profile
| Spec | Value |
|---|---|
| Caliber | 10mm Auto |
| Bullet weight | 150 grains |
| Bullet type | Lehigh Xtreme Defense fluted (lead-free copper) |
| Muzzle velocity | 1425 fps (5-inch test barrel) |
| Muzzle energy | 677 ft-lbs |
| Rounds/box | 20 |
| Case | Nickel-plated brass |
| Primer | Boxer (reloadable) |
| Corrosive | No |
| Intended use | Hunting, self-defense |
| Manufacturer | Underwood Ammo (USA) |
For hunters who run suppressed 10mm carbines or pistols in thick cover, this load’s supersonic velocity and flash-suppressed powder minimize signature while the fluted nose maintains terminal performance through shoulder bone and heavy hide. Compare this load to other Underwood 10mm ammo offerings when you need barrier penetration over expansion-dependent designs.
Safe Handling & Compliance
Federal law requires purchasers to be at least 18 years old for rifle and shotgun ammunition, and at least 21 for handgun ammunition. Ammunition cannot be shipped to certain states, counties, and cities — review our ammunition shipping restrictions before ordering. Store ammunition in a cool, dry location away from heat sources and out of reach of unauthorized users.
- Treat every firearm as if it is loaded; keep muzzle pointed in a safe direction at all times.
- Verify current federal, state, and local laws governing ammunition possession, transport, and use before ordering.
- Nickel-plated cases resist moisture but still require dry storage; inspect rounds for case-mouth deformation before chambering.
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