Full Metal Jacket
FMJ bullets are coated in a hard metal, useful for piercing heavy armor. FMJ bullets are twice as expensive as normal bullets, but treat an opponent's AC as 2 lower, this cannot reduce the target's AC below the target's combined Armor and Natural Armor bonuses.
Jacketed Hollow Point
A more expensive variety of bullet, JHP bullets cost 1.5x as much as normal bullets. The armor (but not natural armor) bonuseof the target is improved by 2 if it is above 0, but damage of the bullet is increased a die-step.
The simplest variety of bullet, they are cheaper than regular bullets by a factor of 10 (thus costing only 1/10th the price) but they are bad for the gun. After every combat in which a weapon fired pure lead bullets, it suffers double recoil until it is cleaned. Cleaning a firearm takes 30 minutes.
Rubber bullets only deal subdual damage, and cost the same as standard bullets, and weigh half as much.