Originally posted by MementoMori
There is no added damage. It is exactly like deep impact from previous titles. Your shot looses less hit points while passing through objects. (note that rapid fire attachment is the same as double tap)
What's so awesome about it? Nothing really. Unless you liked deep impact. I, however, did not. But now rather than having a wasted perk that is never used it is merely an attachment.
I tested it and yes, it add a lil bit of damage too, it means when you have to shoot 4 bullets with the MP5 (long shot) with FMJ you will kill faster, same with the walls etc