I took my BM Dissipator flat top out today for the first time. It has a DPMS detachable sight on it to back up my Aimpoint. Only one problem, I had to bring the aperture all the way to the left to get my groupings correct. At that position they are barely zeroed! BM says that they will have to re-align the barrel. What does everyone think? Thanks in advance for any help.[>:/]