Which BUIS for a High Standard M4gery Upper

[Ripper]

Hi I just bought a Hi-Standard M4 Upper complete, it has a 14.5 in barrel with the Vortex Suppresser pinned and welded to it. It Has a Standard M4/AR Front sight on the barrel. Which BUIS Iron sight do I get for it? I like a folding one because I will put ACOG on it Later Will a troy work or LaRue? Thanks

[FMJBT]

Personally I like the Matech BUIS. They are the current issue sights for military M-4's as well.

[CSTactical]

GG&G, TROY, ARMS, and MI have been good for me.

Mike @ CSGW

[maxicon]

Here's my standard post on choosing a BUIS. Figure out which of these features are important to you, and it'll reduce the field a lot.

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Are you going to mount a magnified optic? If so, you need to consider whether the BUIS will fit under the scope and mount combo - some mounts (like the Armalite) are very low, and others (like the M1Sales) are quite high.

If it's for a red dot/Eotech style, there's a lot more flexibility.

For a magnified scope, you'll need a flip-up BUIS. For a non magnified optic, you can use a fixed sight as well, which is generally sturdier, but obscures part of your field of view.

A few things to consider when choosing rear flip-up BUIS, depending on if it's going to be a range gun or a SHTF gun:

- Will it be used for precision or long-range shooting? A small aperture is helpful for this. If the use is both close-up and long-range, a dual-aperture sight is useful.
- If it's multi-aperture, which one is deployed when it flips? Some flip with the large aperture deployed, others with the small. If you're not in a hurry, this won't matter, but some people care.
- If multi-aperture, do the apertures deploy in the same plane? Some deploy with an elevation shift to account for the range differences, others use the same zero for both apertures.
- Do you want the windage knob easy to adjust or shielded to prevent accidental adjustments? ARMS are exposed and easy, Troy is shielded.
- Does it have elevation adjustments? Some do (like the Wilson Combat), most don't.
- How easy is it to deploy or adjust if your hands are muddy or gloved?
- Does it latch in the up position, the down position, or both?
- Is it spring loaded, like the Matech or ARMS, or not, like the YHM-9680? Spring loaded will pop back into position if bumped, while non will stay partially deployed if bumped from the unlocked position.
- How protected is it from damage, both down and deployed?
- How robust is the detent mechanism? The Matech will wear over time and become easier to deploy (and eventually won't lock). For many, this doesn't matter, as their BUIS aren't used often.
- How many slots does it cover? This is important if you need to conserve rail space.

Figure out which of these are important to you and what capabilities you want, and it will narrow down the choices quite a lot.


Here's how to figure out if it will fit under your scope and mount.

- Measure the scope's eyepiece diameter, with flip caps if you're going to use them. Butler Creek usually adds about 0.1" to the diameter.
- Divide that by 2.
- Subtract that from the centerline height of your mount or rings.
This gives the maximum height BUIS that will fit under that scope/mount combo.

For example, my Leupold VX1 4-12x40 eyepiece diameter is 1.7" with flip caps - divided by 2 gives 0.85". Mounting it in a 1" LaRue LT-104, which has a 1.41" centerline, would leave (1.41-0.85) = 0.56 as the tallest BUIS that would fit. As you can see from the list below, that leaves out many. This is one reason the Troy BUIS is so popular.

Here are some popular BUIS heights:

ARMS 40 - 0.95" folded (mine is 1.00" even)
YHM-9680 - 0.84" to the top of the windage knob, 0.74" to the top of the sight body
Matech - 0.75" folded
MI ERS - 0.75" folded
GG&G MAD - 0.625" folded
Magpul MBUS - 0.625" folded (not verified)
ARMS 40L - 0.61" folded (mine is 0.59")
Troy - 0.460" folded
MI MCTAR-SPLP - .438" folded
YHM QDS - 0.435" folded
KAC 300m - 0.315" folded

[reidnez]

I have the Midwest Industries low-profile and I like it just fine. It's a lot cheaper than the Troy sights, has both small aperature and "O-2" settings and it's well-made. My Aimpoint CompM4 on a LaRue mount easily clears it when it's down. Got it on Riflegear.com, an excellent vendor.

[kakpataka]

is there a buis that has both windage & elevation adjustments? probably not, right?

[FMJBT]

is there a buis that has both windage & elevation adjustments? probably not, right?

Matech, Knights Armament, and quite a few others.

[maxicon]

Matech, KAC 600 (not the 300), and Wilson Combat are the 3 flip-ups I know of that are elevation adjustable.

Matech and KAC 600 have small apertures, while the Wilson is between the standard small and large aperture sizes.

There are lots more fixed BUIS that have elevation adjustments.

[tacticalcity]

Midwest Industries make a great sight and they are fairly affordable. They have forend and gas block versions of the front flip-up mounted sights and they have a couple different versions of their rear flip-up sights as well. I've used them side by side with ARMS, KAC, Troy, GG&G, and others. They are just as good in both performance and quality and they cost a little less and they are usually in stock and ready to ship.

http://tacticalcity.com/minorcategory.asp?MinorCatID=62&CategoryID=1&SubCatID=43

[kakpataka]

I checked out the Wilson BUIs... 179.00
I am wondering if it comes with targets
that have already been shot at!!!