500 yards...
When I was 12 years old, with my '06, I figured out if I wanted to hit a deer at 450yd, I'd need to hold on the spine. Another 6" of air would get me to 500, but that was about my limit with irons, because the front sight covered up the target.
When I got my first scope it felt like cheating.
All those earlier scopes came with screw on covers to protect the adjustment dials against movement and seal the scope from rain in the field, so twisting was out. It was years later the Duplex reticle was considered a great innovation because it could be used for range estimation and with different aiming points once you knew how to use it.
With just crosshairs, at 500 yards it doesn't take any more time to hold on the top of the shoulder as it does to hold 1/3 of the way down. By comparison, Mildots have a wealth of information, but a plain crosshair is fine.
Time spent actually shooting at targets in the field goes a long way.
