How do you use Metal Burst?

Question

I was playing CC on PO, and i had a Bastiodon with Metal Burst. Every time i used it it would fail, how do you use it?

Answer 1

It Deals damage equal to 1.5x opponent's attack. Metal Burst does not do super or not very effective damage, it is the same as Mirror-coat and Counter in that sense.

Answer 2

It doesn't deal damage, it affects the user.

http://bulbapedia.bulbagarden.net/wiki/Metal_Burst