Federal HST is the most widely issued law enforcement duty round in the United States, and the .40 S&W 165gr version is the go-to load for agencies that still field the caliber. At 1,130 fps with 468 ft-lbs of energy, it hits the sweet spot between the snappier 155gr loads and the slower 180gr options. The bullet's skived jacket and pre-programmed nose cavity produce consistent expansion to roughly .70 caliber through bare gel, heavy clothing, and intermediate barriers. For concealed carry, this is the benchmark that other .40 S&W defensive loads get measured against.

The 165gr weight runs noticeably softer in recoil than the original 180gr FBI load spec, which matters during qualification courses and extended training sessions. HST feeds reliably in compact .40 pistols like the Glock 27 and S&W M&P40c, where shorter barrels can cause feeding problems with other hollow points. The nickel-plated brass resists corrosion in holsters and magazines that sit loaded for months at a time. It also makes chamber checks easy in low light.

Home defense is the other obvious fit. The 165gr HST dumps energy quickly and does not typically over-penetrate through standard interior walls the way FMJ rounds do. It pairs well with weapon-mounted lights on full-size duty guns like the Glock 22 or Beretta Px4 Storm. If you carry .40 S&W and want one load for both your carry gun and your nightstand gun, HST 165gr is the simplest answer.