I bought a redfield illuminator 2.5-10x50mm around 7 years ago new. The scope was made in denver. I went to the range today and after looking at the 50mm lense. I saw a round place inside the scope glass right on the bottom of the lense. You can't feel it so it must be inside. Also when you look through it when shooting you can not see it. The gun is still holding zero. What could have caused this, and would you take the chance takeing it hunting? The place looks like a half moon right on the bottom of the inside bell lense.