I really like light weight, but at some point, light is light enough. I used a 1.5-5X 20mm at 9.5 ounces and switched to a VX6 at 14 ounces. The optical performance upgrade for 5 ounces is worth it in my opinion. Now a 20+ ounce scope would be beyond my personal threshold. I think a reason to get a light rifle is to be able to carry a mid-weight quality scope.
