The energy delivered by most 9 mm loads allows for significant expansion and penetration with premium jacketed hollow-point bullets.

The Black Talon handgun bullet is a jacketed hollow-point bullet with perforations designed to expose sharp edges upon expansion.

Cho also bought jacketed hollow-point bullets, which result in more tissue damage than full metal jacket bullets against unarmored targets by expanding upon entering soft tissue.

In addition, improvements in jacketed hollow-point bullet technology have produced bullet designs that are more likely to expand and less likely to fragment than earlier iterations, giving a 9 mm bullet better terminal effectiveness.

A soft lead bullet, or a jacketed hollow-point bullet or soft-point bullet will flatten out on impact (if the velocity at impact is sufficient to make it deform), spreading the impact over a larger area of the target, allowing more total force to be applied without damaging the steel target.

The energy delivered by most 9 mm loads allows for adequate expansion and penetration with premium JHP bullets.

In personal defense use, concerns have arisen over whether clothing, especially heavy materials like denim, can clog the cavity of JHP bullets and cause expansion failures.