I have always admired the design of the rifle scope. It's optomechanics is so minimized, ans so durable, and reliable. The body is tubular, and its design is conical on one or both sides. In optomechanics, conical tubes are so favorable.
What surprised me in these scopes is rifle scopes for air guns must be more shock proof than for real guns. In any case, I tried this on a 22 handgun, and it fell off its alignment after a few shots. The mounting is so critical to keep these rigidly in place.
