I have a chopped carry handle on a carbine that I was sighting in using the IBZ the other day. It has 6 clicks between the 6/3 and 4 on the elevation wheel. I adjusted it to bottom out at 6/3 -4 clicks per the IBZ.

I sighted in using the small aperature and then moved the elevation wheel back up to 6/3 and switched to the 0-2/large aperture thinking the POI would stay the same. My 3 shot group was about 2.5-3" low and according to the IBZ I should have the same trajectory with 6/3 and the large aperture as I do with 6/3 -4 clicks and the small aperture which will give me the same POI for both, right?

I assume my rear sight is screwed up, or is the IBZ slightly off when using detatchable carry handles with 6 clicks between the hash marks?

TIA

Help?

The problem is there are several 'variations' of the rear sight aperture.  If you have the 'corrct' 2moa difference between the small and large aperture then the IBSZ works as indicated.

If you have one of the others - don't fret.  The small aperture is good to go (as are the range markings).  All you have to do is adjust the elevation wheel and learn where it should be for YOUR large aperture.

I should also note when using the large aperture you can see part of the carry handle in the field of view.   This can screw up your sight picture and cause you to aim higher than you would if you couldn't see the carry handle (though it's a more common problem with the larger same plane aperture from XS).  When you are shooting with the large aperture make a mental note to verify the top of the front sight is in the middle of the 'ghost ring' and to disregard any portion of the carry handle that might be seen.