Hi, I did not find any similar questions, After learning this video
http://www.youtube.com/watch?v=dWzs9JA4U4w

I am trying to install my SureFire FH556-212A flash hider, please check the pics A and B, I don't understand which side of the washer, should be face to the rear (bud-stock direction).

Attachment 12789
Attachment 12790