Yugo SKS rear sight question

[cracked butt]

I just noticed this this morning on my Yugo SKS. The rear sight has 2 100 meter settings. The rear sight looks something like this:

-4
3-
-2
1-

--1--

If the slider is aligned with the --1-- , the slider sits atop a step on the sight ramp and is at a higher elevation than at the 1- setting.

Does anyone know what the purpose of this setting is?

 

[railroader]

I'm pretty sure when hte sight is up on the step that is for 300 meters. Mark

 

[embee]

I thought that was for "battle range" - a good, median elevation adjustment for many varying distances out to 200 meters or so.

 

[kart racer]

I'm not sure,but I know at least on mine at the lowest setting at 100-115 yds it is dead on,but at around sixt yds it's still shooting high.