Quick Answer
Hollow point ammo expands effectively on impact when struck at the right velocity and angle. A minimum velocity of around 800-1000 ft/s is required for reliable expansion. Proper expansion also depends on the bullet's design and the target material.
Effect of Velocity on Expansion
Hollow point bullets rely on their soft, thin jackets to expand upon impact. However, they need sufficient kinetic energy to overcome the material’s strength and achieve the desired expansion. Most modern hollow points are designed to expand reliably at velocities between 800-1200 ft/s. Below this range, the bullet may not expand fully or may fragment instead.
Bullet Design and Expansion
The design of the hollow point also plays a significant role in its expansion characteristics. The most common type is the “full metal jacket hollow point” (FMJHP), which features a thin, tapered jacket that expands upon impact. Another popular design is the “total metal jacket hollow point” (TMJHP), which has a thicker jacket that is more resistant to deformation. The TMJHP is often used for hunting larger game, as it provides deeper penetration and larger wound channels.
Expansion in Different Materials
When shooting hollow point ammo, it’s essential to consider the target material to ensure effective expansion. In soft materials like flesh, hollow points can expand to 1.5-2 times their original diameter, creating a larger wound channel. However, in harder materials like bone or metal, the bullet may not expand as much or may even fragment. To achieve reliable expansion in these cases, use a bullet specifically designed for that type of hunting or shooting.
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