Hollowpoint ammunition is designed to expand upon impact, causing a larger wound channel, making it effective for self-defense. Full metal jacket ammunition has a soft lead core enclosed by a metal shell, reducing expansion, and is commonly used for practice due to its cost and reliability. For self-defense, hollow points are preferred as they maximize stopping power and minimize the risk of over-penetration, while full metal jacket rounds are suitable for training purposes to mimic the feel of standard ammunition without the higher cost.