I had 3 Leupols vx3 30mm tubes side parallax cds and two of them failed to dial when changing loads from different bullets weights 140 to 130 grain... Sold all three and now have 2 swfa 3-9 and one trijicon creedo when I turn the dial bullet impact move to where its suppose to... All these years I thought wondering zero and turning the dial and tapping the scope was normal now we all know better thanks to Form.................