^^It looks like the right one. In a nutshell IIRC, one loosens the three screws on the the turret, which allows one to move the reticle. The ballistic cam will also freely move to wherever range it's zeroed at--and then you tighten the screws. Some models of this scope (I think) didn't have the BDC cam--but it was still "rough zeroed" in this way.