Scope rings and moderator

Hello, I put some low mount rings on my Benjamin Cayden, the mag cleared the scope fine, but when I looked three the scope there it was! A nice crescent at the bottom of my scope picture.. I was trying to get the scope as close to the barrel /bore that I could. I am glad that I didn't buy the rings, borrowed from a friend. So if you are trying out different rings be mindful of your moderator.