Magic Bullet is a clientside feature and a type of Silent Aim and when used, a fake bullet is made whereever you are aiming.
How it works
While a normal Silent Aim just changes your angles and shoots (leaving no bullet impact wherever you're aiming on your screen), Magic Bullet also leaves a bullet wherever you're aiming.
Real Magic Bullet
However, there may be a different Magic Bullet hack, in which the bullets land in any place but still get a kill, without being Remote Kill