HoltronSenith means that stopping power multiplys the damage per bullet by 1.4 which in other words means that the damage is 140% of what it would be without stopping power. So if a gun does 30 damage per bullet, without stopping power, it will take 4 bullets to kill in a normal game where players have 100 health (not hardcore where players have 30 health). With stopping power each bullet does 30 x 1.4 which equals 42 therefore it takes 3 bullets to kill. There are more damage multipliers depending on where you hit the person on the body so it can take even less bullets (the head is often a 1.5 times damage multiplier however this varies for each gun).