Operation Shifting Tides will change the way several guns work, which will result in the game feeling more accurate, especially when taking a shot at the chest or head.
The limb penetration system will allow certain weapons to penetrate limbs, hitting the more important stuff, like chest or headshots. Then damage occurs based on the highest-value body part that was in that path. This way, a good sniper round to the face that gets blocked because a hand flew up at the last second will still be a headshot.
Weapons fall into three categories now. Shotguns and machine pistols have no penetration, so what you hit is what you hit. Simple penetration will travel through the limbs on a single target while full penetration weapons like sniper rifles and DMRs have full penetration, with bullets going through multiple bodies if the shot is lined up well. Here is a graphic of the categories.
Level penetration isn’t changed by this, with most weapons still going through a single wall.
This system becomes important with another change will make sure you don’t feel as punished for getting shot in the hand when moving around a corner into view. Hands and arms take as much damage as legs, where under the old system getting shot in the arm was just as bad as being hit in the chest.
Get ready for a very different style of play as angles become more important.
Source: Rainbow 6 Blog