Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.
The Underwood 40 S&W 155gr Hornady XTP JHP pairs Underwood’s full-power loadings with Hornady’s eXtreme Terminal Performance bullet—a combination that delivers 1300 feet per second and 582 foot-pounds of energy from a 155-grain jacketed hollow point. The 40 S&W cartridge remains a proven self-defense chambering for law enforcement and civilian carry, and this load maximizes the round’s terminal performance through controlled expansion and deep penetration. Underwood manufactures this ammunition in the United States, using nickel-plated brass cases, flash-suppressed powder, and non-corrosive Boxer primers. Each 20-round box is loaded to consistent velocities and designed for reliable feeding in semi-automatic handguns.
Load Profile
Underwood builds this round around the Hornady XTP (eXtreme Terminal Performance) bullet, a jacketed hollow point with serrations that control expansion and a swaged lead core that penetrates barriers without fragmenting prematurely. The 155-grain weight sits at the lighter end of the 40 S&W spectrum, trading raw mass for higher velocity—1300 fps from a 4-inch barrel—and flatter trajectories at defensive distances. Nickel-plated brass cases enhance feeding, resist corrosion during storage, and simplify cleanup during reloading. The flash-suppressed powder formulation preserves night vision if you fire in low light, and the cases are Boxer-primed and fully reloadable.
Technical Breakdown
| Spec | Value |
|---|---|
| Caliber | 40 S&W |
| Bullet weight | 155 grains |
| Bullet type | Jacketed Hollow Point (Hornady XTP) |
| Muzzle velocity | 1300 feet per second |
| Muzzle energy | 582 foot-pounds |
| Rounds per box | 20 |
| Case | Nickel-plated brass |
| Primer | Boxer (non-corrosive) |
| Corrosive | No |
| Reloadable | Yes |
| Intended use | Self Defense |
| Manufacturer | Underwood Ammo |
The Hornady XTP bullet’s sectional density of 0.138 and ballistic coefficient (G1) of 0.137 provide adequate penetration for defensive use, and the lighter 155-grain weight produces less felt recoil than heavier 40 S&W loads—an advantage for faster follow-up shots. Underwood tests every lot using real-world firearms to verify velocity and function. This load is suppressor-safe and produces velocities consistent with published data from 4-inch barrels. For additional 40 S&W options, see our full 40 cal ammo catalog.
Safe Handling & Compliance
Federal law requires purchasers to be at least 21 years old 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.
- Follow the four rules of firearm safety at all times: treat every gun as loaded, never point at anything you don’t intend to shoot, keep your finger off the trigger until ready to fire, and know your target and what lies beyond it.
- Verify current state and local laws governing ammunition purchase and possession in your jurisdiction before ordering.
- This ammunition contains lead. California Proposition 65 requires warning that lead exposure can cause cancer and reproductive harm. Store away from food and wash hands after handling.
Reviews
There are no reviews yet.