No I do not carry my rifle by the scope. I either carry the rifle by holding the pistol grip in my hand and resting the rifle on my shoulder or have the rifle cupped in my right hand or carry the rifle cupped in the crook of my left elbow and holding the rifle grip in my right hand.Or I carry in a ready position with the rifle pulled close to my body and all I have to do is raise the butt of the rifle and shoot. About all I use a sling for is when I climb into a tree stand.
I dont see how a person could carry a rifle by the scope unless it was in very high mounts,only way I could carry any of my rifles by the scope is the scoped AR I have. Mt other rifles are scoped bolt actions and there is room for only my fingertips(fingers will not slide between the rifle and scope) to go under the scope in a curling or pinching, fashion with the tip of my thumb from the other side. Not very Much control of the rifle and I would have muscle spasms in my fingers in probably less then 20 steps !
And I have average to small hands and fingers.
I just tried an Old Mauser 98 with a Leupold 4x28 in higher mounts so bolt handle can clear scope and I can If i wanted to carry it by the scope. Cant see me wanting to though as it would be much slower to bring into action and the weight of the rifle would bearing on a much smaller area of my hand than the other ways of carrying.
