BUIS/Optic Drop Test

In early May, I performed a BUIS drop test which was partially published on Military.com’s KitUp blog several days ago.

The unpublished portion involved an EOTech 552 and an Aimpoint CompM3. The EOTech used the standard thumbscrew mount, and the Aimpoint was in a GDI CMC7-OSM mount.

To be fair, my EOTech 552 has seen better days.

POI shifted 12MOA to the right with the EOTech, POI shift was 1MOA or less with the Aimpoint.

Aimpoint CompM3 in GDI mount. The Aimpoint wasn't exactly new either.

One thing I did not mention in the post which was sent to KitUp (due to word count limitations) was that after dropping the MBUS twice, I picked the rifle up, held it over my head like the maul I used to split seasons’ worth of firewood while growing up in Alaska, and swung it down on a concrete shooting table, with the MBUS taking all of the impact. It did not break or shift POI by anything more than 1MOA.

My opinion of the MBUS went from “cool airsoft gear bro” to “wow.”

For the record, the only pieces of gear used in this test which were not provided to me for free by a manufacturer or dealer were the MBUS, EOTech, and Aimpoint. The Diamondhead, Troy, and GDI Aimpoint mount were provided by Rainier Arms, Spike’s Tactical, and GDI, respectively.

Magpul MBUS after being dropped (while attached to a rifle) twice and swung onto a concrete surface with force.

30 thoughts on “BUIS/Optic Drop Test”

  1. curiosity has me, do you think that awesome gdi mount had anything to do with the maintaining of zero? what I’m getting at is was the shift inside the optic or something about the optic being physically shifted in relation to the gun?

  2. In the words of Adam Sandler in Wedding Singer, “Information that would’ve been useful to me yesterday”

    Not literally, but last year when I was BUIS shopping, I shied away from the MBUS because I felt a lot of the info I could find was either marketing or fanboy. I opted for Troy

    This is good info for the future, thanks.

    And I only run Aimpoint RDS so I’m good there.

    By the way, when reading about your swing test, I had this image of you re-enacting the Sandpeople kicking Luke Skywalker’s ass, except with the rifle instead of the stick.

  3. I have MBUS on my S&W 15-22, but use Troy for 5.56 assuming it to be higher quality. Even been alittle put off by gun companies like Colt putting MBUS on their firearms. Guess I need to rethink my opinion.

    Funny you mentioned airsoft, been thinking about getting a M4 airsoft for backyard use and was thinking a MBUS mated to a Primary Arms red dot would work nice. Cool factor is important.

  4. Crap. My AR fell from leaning up against a wall to a cement floor, and the Troy rear BUIS took the hit, bending the right-side ‘guard’ in towards the sight.

    I spend the extra for a Troy because metal should be stronger than plastic, right…

    1. Well, it depends on how you define strong. In this case, the plastic won out over your metal BUIS because plastics like Magpul’s polymer are more likely to flex and deform elastically, whereas the (relatively) thin metal of the Troy BUIS just deformed plastically.

    1. Not sure where the hate came from… I’d like to say because of the ACR (understandably), but I think it’s mutated into, “just because they’re popular,” but no one will admit to it. Me? I just want whatever works, Magpul or not.

  5. I don’t use my rifles for anything serious, so the MBUS have been suiting my needs just fine. They get used for occasional irons practice and also make for an easy zero when I play swap-the-optic. It’s good to hear that they can take a beating, even if I’ll probably never give them one.

  6. Way to fuel the “EOTech vs Aimpoint” fire… I can’t wait to see it hit the forums, so I’m going to post it there right now. :p

  7. I wonder how an A.R.M.S. #40 or #40L would do, as it folds down, rather than staying locked up….

  8. I’ve experienced a similar degree of impact shift using an Eotech on an M1A SOCOM. It’s a heavy weapon to drop on any sight, but ~10 MOA shift is inexcusable.

    I’m pretty surprised about the Magpul sights, but I’ll be using/testing a set on my next AR.

  9. the EOTech shifted 12 moa? was it a failure of the optic or the mount? do you think the overall life/possible abuse of the EOTech in the past may have contributed to the large offset?

    perhaps this might be a good case for back up sights.

    1. Yeah, there seems like there must be more to that 12 MOA is a lot…..and I already hate eotech just because if you have to use it day in and day out they just have not been very reliable for me. They go through batteries like crazy, battery grommets fall out and get lost (site is useless), turns off during recoil, over-sized, over-weight, hard to reach controls, can’t leave it on (auto turn off, sucks for operational use).

      I know i am biased, but these are all problems I have had personally, not something I read on a website. These are from using these for the past 9 years or so. I am sure they work fine for taking out to the range or if they are taken care of better, if you have the “right” one that doesn’t have the issues I am talking about, but I don’t like to leave things up to chance. There are downsides to aimpoints, but I think they are more reliable and battery life is unmatched.

      1. Thanks been leaning towards an eotech but never had hands on. Lots of good points appreciate your experience, will be looking at another sight.

  10. I’ve been pretty pleased with the MBUS. The spring loaded flipperoo hasn’t proven to be super important but I like that they’re easy to get down and out of the way since I “true” co-witness. At that if for some reason it’s up (which is rare) I tend to have the sights lined up anyway. I hike around hunting and so I do end up experiencing how the junk on my gun works for good and bad for the role it’s in which has nothing to do with defense. I haven’t dropped mine but they have been victim to being bumped on gear and just not given special care. I think they’re a keeper in most cases.

  11. I’d like to see an ACOG (say TA31F) and Knight’s Armament’s backup sights tested. The KAC iron sights are by and large the only folding BUIS (or BUIS period) that seems to be deployed by the US military. I love mine, but considering their price and relative scarcity I’d rather not test them myself. Barring that, I’d say they’re the best shooting BUIS I’ve tried, perhaps excepting LMT’s fixed front and rears that perfectly emulate the A2 sights without the carry handle.

  12. Great test. And here the armory kept trying to sell me Troys to replace my MBUS, because you know, they are stronger…

  13. I ended up with KACs on my “dream ar” build. I’m not to worried about it, considering The only people with back ups in Afghanistan were the IAR gunners and snipers. Being in the military, you realize nothing is unbreakable. I can think of no situation outside of being “in the field” for an extended period of time where a user would damage his primary and buis beyond use and lose his life as a result of it. Something is better than nothing, but Id he hard pressed to find anyone in there day to day life who needs to sweat not having the strongest buis.


  14. I think this is an unfair comparison of an optic with a high end aftermarket mount vs a thumbscrew mount. The GDI mounts are incredibly over-engineered to hold zero and RTZ to .5 MOA while the thumbscrew design isn’t as durable and offer no return to zero. It could’ve been the mounting solutions or it could’ve been the optics but in the end I felt this wasn’t an equal battle between the two. Just my thought.

    1. I tested what I had. If you’d like to pay for something else to be tested, I will happily do so.

      1. While I certainly won’t be mailing you any toys I’d love to see an EXPS get compared. That 12 MOA made me sad.

  15. I had never been a fan of the MBUS sight, they seemed weak and like you said “airsoft gear”.

    Might have to rethink that idea now.

    Great article.

  16. Thanks for your efforts, Andrew. Very timely. I bought the MBUS rear-sight instead of the Troy. The $60 savings bought 200 rounds of Federal M193 on sale at Cabelas. Thanks, man.

  17. Matech is widely used with SOPMOD kits so that should be tested at some point.

    Also front sight BUIS should be tested both folded down and in uprigth mode. Even when not in use they take a beating. Problem for testing is that the gas block or free float tube can and will take a beating too. Is the shift caused because the front sight itself failed or because the piece it is attached to fails.

    Anyway an interesting test. Often the rear BUIS sits safely below a Leupold or S&B scope so I would like to learn more about the toughness of front sights

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