RBIZ, BCM A4 Clone, and ridiculous adjustment requirement

[Eurodriver]

I'm shooting Lake City M855 out of a 20" BCM A4 w/ KAC M5 and BCM Carry Handle Rear Sight.

The rifle is zero'd at 6/3-6 using the RIBZ at 100 yards. When I move the adjustment knob to the "4", I am shooting about 3 feet high at 400 yards. Shooting position is the same, POA is the same, there is no other change other than going from 6/3-6 to 4 on the rear sight drum.

The front sight post is already unscrewed so much that I can see light underneath the base of the sight in order to zero it at 100.

What is going on?

[223to45]

Sorry not much help, but what is RBIZ??

[C-grunt]

What distance is your rifle zeroed at for the -6 setting?

[Eurodriver]

What distance is your rifle zeroed at for the -6 setting?

Sorry, updated OP. 100 yards.

223to45,

See here: http://www.ar15.com/forums/t_3_18/328143_RIBZ_____Revised_Improved_Battlesight_Zero.html

[samuse]

6/3 -4

[Leaveammoforme]

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