I just mean that on a regular target, the black is say 6 3/8" across. There's concentric circles around that (and in it) making up the various rings. The ten ring (or X ring depending) is in the center, about 2" across.
Open sights for me, at 100 yards on that target is no problem. I can hit the black no sweat, which means a shot in the 10 or 9 ring (or 10 9 or 8 if the target has no 'x' ring)
To do that I center the entire 6 3/8" black in my open sights.
I was shooting at a 2" target dot, stand-alone on the paper, that was the whole target. That would be tough for me with say my M1 even though I could see the 2" dot through the open sights because the target is visually so small compared to the sights- on that 2" target, I'd have to center a target roughly 1/3 the size of the 100 yard target in my open sights
With my scoped 03A4 replica, the mild magnification plus the precision of the crosshairs makes that a much easier shot, even though, say, my M1 and that 1903A4 replica are probably equally as accurate.