Co-witnessing flip-up BUIS with a red-dot

Co-witness means your iron sight line and your optic’s reticle can share a usable picture when the irons are raised. The Ozark Armament FBUIS-B flip-up set is built for that role on Picatinny: fold flat for an open optic window, flip up when batteries die or glass fogs.

View FBUIS-B on Amazon

Absolute vs lower-1/3

• Absolute co-witness: irons sit in the middle of the optic window; the dot and front post stack on the same sight line.
• Lower-1/3: irons sit in the bottom third of the window so the center stays clear for the dot until you deliberately look down at the posts.

Which you get depends mainly on optic mount height, not on marketing labels on the sights. Place the FBUIS-B front and rear so their heights match each other, then test with your optic before you finalize rail slots.

Setup checklist

1. Mount rear sight far enough back for a natural cheek weld; mount front near the muzzle end of usable rail.
2. Seat recoil lugs in Picatinny slots; tighten with the included hex driver.
3. Raise both sights; look through the optic. If the posts sit too high or low in the window, change optic riser height or rail positions—don’t force it with extreme elevation clicks alone.
4. Pick the rear aperture (small for precision, large for CQB) before you zero.

FBUIS-B facts (ASIN B01AISP1KW)

• Aircraft-grade aluminum front + rear flip-up pair
• Spring-loaded · Picatinny · windage/elevation dials
• Dual rear apertures · set weight 3.84 oz
• Model FBUIS-B · UPC 784672554763 · seller Ozark Mountain Supplies (FBA)

Buy Ozark Armament Flip Up Iron Sights (FBUIS-B) on Amazon