The issue isn't so much the weight of the scope. The issue is where the weight is located in relation to the rest of the rifle's weight. Also the sheer size of the scope is a factor (especially the fixed powers or 3-15) when used on a light, slim rifle.
Bolt a 20 ounce, bulky scope to a Ruger 77 300 Mag, and it's not going to have nearly the same effect on handling as when it's bolted to a slender Kimber 84M. The Kimber is easily overwhelmed. It's like loading a dead moose on the top of a Suburban vs. loading the same moose on the top of a Yugo. Which one is going to handle the load better driving in traffic?
