Thanks! After looking again, I found what I was looking for. It wasn't exactly what I had pictured so i was overlooking it but I am sure it is the right one.
That is one of the references I have already used. Unfortunately it is not on there. This might be an older marking I think but I can't seem to find anybody who has ever seen it before.
I am trying to identify the manufacturer of a cap screw. It is a grade 8 with a head marking of double overlapping hexagons. I have looked through all reference material I have and none of them show this head marking. Are any of you familiar with this?