Piercing
Piercing damage (pi-, pi, pi+, and pi++) attack involves a fast, blunt projectile, such as a bullet, or is sharp but too small to qualify as impaling, like a dart or a stinger. It may inflict blunt trauma, and can target the eyes and vital organs. There are four subclasses of piercing attack:
Small Piercing (pi-): Used for very low-energy projectiles (e.g., blowgun darts), or for attacks that tend to punch through the target and leave a small wound channel (e.g., armor-piercing bullets). Against flesh, halve damage that penetrates DR.
Piercing (pi): Used for most rifle and pistol bullets.
Large Piercing (pi+): Used for attacks similar to large-caliber solid bullets, or for smaller projectiles that create large wound channels (e.g., hollow-point bullets). Multiply penetrating damage in flesh by 1.5.
Huge Piercing (pi++): Used for attacks that leave an even larger wound channel than large piercing. Double penetrating damage in flesh!
Piercing damage is subject to Overpenetration.
Against Flexible Armor: For every full 10 points of piercing damage stopped by your DR you suffer 1 HP of injury due to blunt trauma. This is actual injury, not basic damage. There is no wounding multiplier. If even one point of damage penetrates your flexible DR, however, you do not suffer blunt trauma. If you layer other DR over flexible DR, only damage that penetrates the outer layer can inflict blunt trauma.