Great but.... - Magpul Industries Enhanced Ejection Port Cover

The cover looks great and is way easier to install then your regular mil-spec cover. However, for those of us who are installing on an Aero Precision M4E1 upper, the ejection port cover can be stiff and not fully open. I had to lightly sand the the lower portion along the hinge that was rubbing aganist the receiver. I also added tiny bit of oil to the hinge point and now works like it's suppose to.