Wednesday, September 27, 2023

MagPul Back-Up Sight (MBUS): Polymer Flip-Up Sight/BUIS System

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By David Crane
defrev at

All photographic images contained in this article were taken by, and are the exclusive property of owns the copyright on these photos. All photos were shot with an Olympus Stylus 790 SW 7.1-megapixel digital camera, which is advertised as "shock + waterproof".

February 25, 2009

Updated on 3/13/09

MagPul Industries had more than just a new tactical carbine/rifle sling at their booth at SHOT Show 2009. They actually had a plethora of new tactical goodies (i.e. tactical accessories for tactical rifle/carbines), including the new and very cool MBUS (MagPul Back-Up Sight) polymer flip-up front (MBUS F) and rear (MBUS R) sight system a.k.a. polymer BUIS (Back-Up Iron Sights) or BUPS (Back-Up Polymer Sight — thanks, Say Uncle!) system that looked like it would be right at home on the rails of the PWS Diablo AR-15 SBR (Short-Barreled Rifle) that we also discovered at SHOT.  The new MagPul MBUS flip-up BUIS system utilizes a neat ambidextrous integral pressure switch-type release and locking system that both releases the flip-up sights and locks them down.  To release the sight (i.e. flip it up), just press down on the ambidextrous lever with your thumb.  To lock the sight(s) back down, just push the sight(s) down (by pushing the flipped-up portion, i.e. sight body down) until it/they lock(s) back in place in the down/flat position.  Piece of cake–and pretty slick execution.

DefenseReview believes in having a good pair of flip-up sights (flip-up front and rear back-up iron sights) that you can co-witness with your glass combat optic (optical combat sight), and that will be there for you in case your optic goes down or gets damaged, and the MagPul MBUS system looks good.  Needless to say, we look forward to trying the MagPul MBUS-F and MBUS-R polymer flip-up sights/BUPS out on one of our tactical carbines or SBRs very soon. In the meantime, here are a few photos:…

Addendum 3/01/09: Say Uncle makes an interesting point when he says that perhaps instead of calling it the MagPul Polymer BUIS, it should be called the MagPul BUPS (Back-Up Polymer Sight) System. However, since the primary sighting components themselves are made from metal (presumably steel), calling them a Polymer BUIS system is appropriate. We’ll let our readers make the call.

Company Contact Info:

MagPul Industries Corp.
PO Box 17697
Longmont, Colorado 80308-0697
877-4MAGPUL (877-462-4785) Toll-Free Office
303-828-3460 Office
303-828-3469 Fax
[email protected] Customer Service/Orders Email
[email protected] General Email Website

DUNS # 076925788

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MagPul Back-Up Sight (MBUS): Polymer Flip-Up Sight/BUIS System by

About David Crane

David Crane started publishing online in 2001. Since that time, governments, military organizations, Special Operators (i.e. professional trigger pullers), agencies, and civilian tactical shooters the world over have come to depend on Defense Review as the authoritative source of news and information on "the latest and greatest" in the field of military defense and tactical technology and hardware, including tactical firearms, ammunition, equipment, gear, and training.

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