Magpul MBUS Back-Up Folding Rear Sight

$55.05 $35.00
(You save $22.95 )
(57 reviews)
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The Magpul MBUS (Magpul Back-Up Sight) is a low-cost, color injection molded, folding back-up sight. The dual aperture MBUS Rear Sight is adjustable for windage and fits most 1913 Picatinny rail equipped weapons, but is specifically tailored to the AR15/M16 platform.

Made in U.S.A.


  • Impact resistant polymer construction provides light weight and resists operational abuse
  • Spring-loaded flip up sight easily activated from either side or by pressing the top
  • Detent and spring pressure keeps sight erect but allows for unobstructed folding under impact, etc.
  • Clamps to MIL-STD-1913 Picatinny/STANAG 4694 receiver rail and provides the same height-over-bore as standard A2 irons
  • Protective wings shield the dual, same plane flip apertures
  • Sight can still be folded with either large or small aperture in position
  • Detent knob easily and positively adjusts windage


  • Weight, w/ hardware: 1.3 oz.
  • Height above rail, stowed: ~0.51 in.
  • Center of aperture to top of rail: 1.42 in.
  • Length, stowed: 2.6 in.
  • Length, deployed: 1.5 in.


  • 5
    Best BUIS

    Posted by Andy on 22nd Feb 2024

    Love these sights. With the side and upper flip up, makes it easy to activate and use. Love as it's low snag and compact. It's my favorite BUIS.

  • 5

    Posted by Hector Ruiz on 10th Dec 2022

    Love these sights. So easy to adjust/zero in and they stay on point/target.

  • 5

    Posted by Anthony on 20th Jun 2022

    Shipping was timely and product was 100% well made in USA! Will be using arms unlimited again.

  • 5
    Better late than never…

    Posted by Adam Harris on 15th May 2022

    See above

  • 5
    Just what I ordered!

    Posted by David T on 26th Apr 2022

    Works and looks great!

  • 5
    A bit tight but it’s ok

    Posted by Gen on 24th Apr 2022

    I thought I’m going to have a problem when installing the sight to my bcm upper because it seems too tight, but with a little bit of encouragement with a rubber mallet, it went through.

  • 5
    Magpul back up folding recite

    Posted by Frank Badial on 3rd Mar 2022

    Great price very very very quick shipping. A pleasure to do business with a company like this one.

  • 5
    Works great

    Posted by Unknown on 17th Feb 2022

    These sights do what they're supposed to do. Never had a problem with any of them and at this price it's hard to beat.

  • 5

    Posted by Chris Padilla on 29th Nov 2021

    Excellent sight. Easy install. Delivered fast and secure.