So originally I received my scope and looked through the glass It had small bubbles visible. Not a high point for me. I like clear glass. But I had waited almost 4 months to get the scope so I mounted it anyways. When using it a full magnification the defect is not visible. Then I zeroed the Scope on my 20 inch, heavy barreled AR-15. All I can say is I am glad I waited and didn't cancel my order. It performed way better than I expected, so much more that I will most likely mount this on a bigger rifle. Way to go Arken. I probably will not be returning this scope.