Digging the MBUS Pro: Peep Sight Done Right

Digging the MBUS Pro: Peep Sight Done Right

I am hands on with the MBUS Pro and I have some good things to say about the product. This product had been out for ages, so this isn’t a review per se… but it is a bit of a feature review because no one else seems to mention a very important feature this BUIS has to offer.

One of the key features of this sight is that it has a large area of which it blacks out light around the aperture. This “eye cup” is an important, but poorly understood, feature of a peep sight. Peep sights, by nature of their design, suppress parallax. The effect is further enhanced when your pupil is dilated. Sound weird? Say what?

Take a read:


The brightness (luminance) of the environment, of course, affects the diameter of the eye’s entrance pupil. Thus in a darker environment the amount of eye shift permissible before parallax suppression degrades into parallax reduction is greater than in a brighter environment. Typically, the rear of the rear sight has a dull black finish, said to reduce “glare” and to enhance the contrast with which the front sight and the target are seen. But fortunately, this also reduces the average brightness seen by the eye, and causes the eye’s pupil to enlarge. This of course enlarges the range of eye movement for which we have full parallax suppression. In some precision sights, this effect is enhanced by way of an “eye cup” surrounding the aperture disk proper.

So the “eye cup” is an important component of peep sights as we want to reduce the amount of light that bleeds to the eye to help reduce parallax error. In the case of the MAGPUL MBUS Pro, we have a very clean sight picture that occludes (or blacks out) a large area of the field of view from the shooters eye. This in turn will hopefully decrease the brightness and force the pupil to dilate and further enhance the parallax reduction of the peep sight. I noticed online that the Magpul MBUS had an excellent profile and features one of the largest eye cups on the market.

Overall the construction is solid and the sight picture is just as I had hoped. It’s very occlusive, the sight picture itself is very clean, and the rear gathers no light or glint… just a black tower in front of the eye with a perfect hole from which to acquire the front sight. I look forward to getting this zeroed soon.

Magpul MBUS pro

A recessed eye cup with a scalloped face to reduce glare. Really well thought out by Magpul.

Written by lothaen


  1. E.D.M. · June 21, 2015

    I have the LR version, and have been quite happy with it. I haven’t gotten to take it out and test the range dialing feature, though.

    • lothaen · June 21, 2015

      I almost purchased that one, but the Magpul care package I purchased for myself was getting spendy so I decided to downgrade. Every cent helps when your blog has you in debt!

  2. NJ · July 30, 2015

    Valuable comment on the MBUS Pro sights.

    I bought these sights a few months ago for my short-barreled AR-15 (10.3″ barrel).

    A few of the other things I like about these sights:
    – the center of the small and large apertures are both in the same plane. Unlike the MBUS Pro, many (most?) carry-handle and flip-up sights with two apertures in an L-shape (e.g. one aperture for 0-200, the other for 200-600), there’s a slight left-right offset when you flip from one to the other. It’s tiny, but those thousandths of an inch at the rear sight translate to inches or feet at the target. The MBUS Pro doesn’t have that issue.
    – low height above the top rail when flipped down
    – positive, solid lock when up, unlike many flip-up sights, where it’s harder to tell when they haven’t locked properly in the UP position. (Again, those nasty little thousandths of an inch at the rear sight that translate to inches or feet at the target.)

    One thing I would have liked:
    – the option to install a wider front post than the mil-spec default.

    Thank you for your blog!

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