Damage falloff is the amount of damage a bullet loses the further it travels. This will be an example (the stats are just a guess but used for illustration purposes): Up For Anything auto rifle. Range 20M Each bullet does 25 damage each hit up to 20m out. After 20m, the damage is reduced the further distance the bullet travels. So, say at 35M, rather than 25 damage, each bullet does 18 damage. These stats are nowhere accurate and used simply for example purposes. Damage falloff is the reduction in damage per bullet once it has passed it's base range.