I’m running a 16” Oly barrel with a standard Oly FSB and Bushmaster CCH BUIS. I recently swapped out my Oly front sight post for the Bushmaster .040” taller front sight post because my original sight post sat up higher than normal, the typical problem often encountered. This original setup was zeroed using the Santose IBSZ at 50m.

With the new .040” FSP installed at mechanical zero  I zeroed at 50m and was hitting about 9-10” above center. I adjusted the FSP out to bring down my shots and ended up with the FSP extended out like the original Oly standard FSP I replaced!

Back home I read the Santose IBSZ instructions and realized that during my zeroing I forgot to turn down my elevation knob the -4 clicks past 6/3 as stated below:

6. Battlesight the rifle per the -10 with the following exceptions:

1. Sight should be at 8/3 -2 clicks, that is, all the way down, not up a click.  Please note removable handle sights are marked 6/3 (rather than 8/3); also some are in `half-clicks' as well. There should be 3 clicks between 3 and 4 on the knob. If there are 6 clicks then the sight needs to be set at -4 clicks (instead of -2).

Could this be why my POI at 50m was extremely high and my taller FSP still ended up sticking out higher than normal? If I had zeroed at 50m with the elevation drum turned -4 past 6/3 then my taller FSP would not have been so high up and my adjustments not as drastic?

Another question, in the Santose instructions it states:

7. Remember you're adjusting the FRONT SIGHT for elevation, not the rear, and that each click is about 1/2" (actually a little more) at 50 yards. You won't get it closer than that. Don't frustrate yourself trying.


8. You're done. Leave the sight in this position for 99% of your shooting.

So do I read this correctly, the sight remains at the -4 clicks past 6/3? And if engaging targets at 300m or greater then I would rotate the drum up to 6/3 or higher as needed?

Thanks,

Quib

Quoted: Could this be why my POI at 50m was extremely high and my taller FSP still ended up sticking out higher than normal? If I had zeroed at 50m with the elevation drum turned -4 past 6/3 then my taller FSP would not have been so high up and my adjustments not as drastic?

Yes.  When all else is equal adn you raise one sight you'll have to raise the other site to still have the same POA/POI at athe same range.

So do I read this correctly, the sight remains at the -4 clicks past 6/3? And if engaging targets at 300m or greater then I would rotate the drum up to 6/3 or higher as needed?

You leave it at 6/3-4 when using the small aperture that you zeroed with to shoot at targets that are out to ~200 meters.  If they are more than 200 meters away then you use the small aperture and set the ranging wheel to the appropriate setting.  For normal shooting out to ~200 meters you should use the large aperture and set the wheel to 6/3.  Remember that the two apertures are not at the same height.