I'm having trouble trying to understand the topology & model this shape I'm trying to model the HK G11 but this part just confuses me. 



I tried to model it and it looked alright but the "flow" was still not close to the real thing. I don't know where the poles should be and if my way of doing it was bad or not.  If you want to give me some general ideas on how to do it or recommend me a related tutorial that would really help me.
To me it looks like something like that: