idk if it is true... it worked for me maybe its just a coincidence

1. get a gun with laser sight and a high suppresor
2. put it in automatic
3. lock on and slowly move to a side while locked on

* reason it kills fast is the aim is closer to the head, usually gets a head shot in around like 3 seconds

Well ya... Der u go

Im not taking credit for this method.

Go now and try it out :)
have a nice day