This is a mount and BUIS I bought a few years ago for my Bushmaster.  I want to duplicate the same set-up on another AR.  The BUIS is lined up perfect with the dot.  Problem is I don't remember where I got em.  The memory is the first thing to go I guess.  I believe the iron back up is from DPMS.  Can't find the damn Aimpoint mount anywhere.



Thanks for any help in advance.

Aimpoint QRP mount......DPMS BUIS.

Doh!

Damn I owe you a beer!  Thanks a' Ton.

Rob

Something I don't understand.   On the RRA site they say: "Aimpoint Spacer Required to co-witness with QRP"  My QRP shown in the picture is without the spacer and it lines up fine.  WTH?

Rob

With out the spacer you get an absolute co-witness. With the spacer you get a lower 1/3rd co-witness.

Uhmmm

Ok can you explain the differences?  

Rob

Quoted: Uhmmm Ok can you explain the differences?   Rob

Absolute co-witness is when the BUIS sights are exactly in the center of the optic when viewed through the optic. Like what you see now when you look through the set up you have posted above.

Lower 1/3rd co-witness is exactly that….when viewed throught the optic the BUIS appears in the lower third of the optics window.

This is not the best example but if you can imagine the rifle in the picture below having the BUIS flipped up into position and centering the front sight through the BUIS, the whole iron sight system would appear in the lower third of the Aimpoint window.

10-4

Fully understood now.  Thanks.

R