I have just figured out that neither the front or rear action boss is contacting the inlet mount surface of the Oryx chassis.

And as Fuj' said above, the Oryx is a v-block type chassis except the V is not deep in the chassis like I expected like a Choate stock.
The V is a chamfer on the sides.

Dont know why it took me so long to figure this out.

Anyway, all is good.

Thanks everybody.