Please help me choose a BUIS for my AR

[ShootAndHunt]

I just bought the EoTech for my RockRiver middy flat-top AR, this Holo-sight is very nice. However, it is electronics, and as we always said, you cannot never depend totally on something using batteries and chips (plus sometimes I just want to use the iron sight for some old shooting fun), so I want to get a BUIS (back-up iron sight). Since I never buy one before, could you experienced guys help me to choose one?

I just know that I want a foldable BUIS, because the EoTech will be my primary sight, but besides that, I don't know what else I should look to. I heard that ARMS, GG&G, Troy make some good BUIS, are there any very nice model? Could you recommend me some? The BUIS may not need any elevation adjustment ability since it is, just as its name said, a back up, but I still want windage adjustment ability. I also heard that ARMS has a BUIS which is called same plane, is it any good? Where online I could find some good price on these BUIS?

Thanks in advance,

 

[TexasRifleman]

Well, I am not a fan of the "same plane" sight systems, because that means the front sight is always in line with the EoTech.

The best solution, in my opinion, is a combination of the Troy BUIS and the LaRue mount for the EoTech, as shown on my AR below.

What this gets you is a BUIS that is usable through the EoTech window should something go wrong, but that raises the EoTech up so that during normal usage the front sight is below your sight picture with the EoTech.

When using the BUIS, you can see fine through the EoTech, just using the lower third or so of the window.

As for where, I do business with Grant at G&R Tactical, always treated me well.
http://gandrtactical.com/

 

[rbernie]

I am not a fan of the "same plane" sight systems, because that means the front sight is always in line with the EoTech

Spoken purely out of ignorance - why is that a problem?

 

[TexasRifleman]

Spoken purely out of ignorance - why is that a problem?

I am not a fan of the same plane
sight systems. They serve no purpose. If your BUIS is deployed, then your primary sight is not being used any longer, so why would you want things to line up (which they won't anyway)?

The EoTech reticle is not stationary in the window, and in most cases the 3 sighting elements will not line up anyway if you happen to have the BUIS deployed at the same time as the EoTech. So, why have the front sight visible in your primary line of vision at all? I prefer the reticle above the front sight
That is the purpose of the LaRue mounts, to avoid this. Also, with the raised mount, depending on your stock, you may be able to get a better cheek weld, but that's something you have to try out personally. Some like that, some don't.

Edited because I read to fast and have a big mouth.

 

[Jeff White]

TexasSIGman,

What's the offset and holdover for that rig from 0-25 meters?

I use an aimpoint co-witnessed and have never had any problem noticing the front sight in the FOV.

I'm of the keep it simple camp when it comes to BUIS. I've found the KAC 300 meter BUIS works well for me. I've never seen the need to have a backup sight that was adjustable for both windage and elevation. I just zero at 50 meters (gives a 200 meter battlesight) using the front sight post to adjust elevation and leave it there.

Jeff

 

[TexasRifleman]

TexasSIGman,

What's the offset and holdover for that rig from 0-25 meters?

I use an aimpoint co-witnessed and have never had any problem noticing the front sight in the FOV.

I'm of the keep it simple camp when it comes to BUIS. I've found the KAC 300 meter BUIS works well for me. I've never seen the need to have a backup sight that was adjustable for both windage and elevation. I just zero at 50 meters (gives a 200 meter battlesight) using the front sight post to adjust elevation and leave it there.

Jeff

With 75gr TAP, it's about 2 1/2 inches high although this weapon is clearly intended for use inside of 100 yards so I have it zeroed at 60 yards or so.

There is no offset at all.

The little LaRue mount isn't as thick as it looks in the photos, so you're really only raising the sight maybe 1/4inch, if that. The EoTech side rails hang over the sides and hide the mount so you can't really see that from the photo, but it's not high as it looks.

And again, we're talking an EoTech here, not an Aimpoint. I have never used an Aimpoint so I don't know if it is the same, but the EoTech reticle dances around a lot and, in my opinion, the front sight blade adds to the clutter.

I agree that there is no reason for a fancy adjustable BUIS.

Another thing I like about the LaRue mount, although I haven't played with it much, is the little rail behind the sight. You can use the Aimpoint 3x magnifier on that little rail and not have to remove the BUIS. I thought I would use that more than I do, but it's another reason I like the mount.

 

[rbernie]

.

 

[Coronach]

Yeah, I think we can officially call a halt to that, right now.

Coronach

 

[TexasRifleman]

4 tap? That's weird.

 

[TexasRifleman]

weird, triple tap

 

[TexasRifleman]

Holy cow, TXSigMan - it was an honest question. Calling me a moron and otherwise abusing me for asking for clarification about something that I admittedly had no first-hand experience with is simply uncalled for.

You wanna continue abusing me for asking questions - do it via PM.

Edited for stupidity. (mine).

 

[TexasRifleman]

doubletap

 

[rbernie]

.

 

[TexasRifleman]

I didn't call you ignorant - go back and read the post. I said that MY QUESTION WAS POSTED OUT OF IGNORANCE.

Geez - if you're gonna be so bloody quick on the draw, at least be sure of your target.

Oh crap. You're right, and since I mouthed off about this being the High Road, my apologies. Truly sorry.
I'm a moron.

 

[Coronach]

Quad-taps notwithstanding, read my post above.

Coronach

 

[NMshooter]

To get back to the topic...

I have used the ARMS #40 and #40L for years, they work well.

A folding BUIS is not necessary for non magnifying optics, but with magnification you either have a folding one or go without. You want the lowest profile you can get to fit under the eyepiece, the #40L and KAC sights work, and anything similar.

Whatever you get, use Locktite when installing, this will help keep zero.

 

[JeepDriver]

I have the ARMS 40L on 2 of my rifles and love it.

I hardly notice it's on there (which is a good thing). Low profile and out of the way until you need them is what a BUIS should be(too me atleast). I doubt, and hope I woun't have to use them, I should be able to count on my electronic sights 100% or the time.

 

[rbernie]

If your BUIS is deployed, then your primary sight is not being used any longer, so why would you want things to line up (which they won't anyway)?

In my naivete, I would have expected co-witnessing to be theoretically useful in ensuring repeatability when shouldering the weapon and acquiring a target - keeping the head and eyes in the same place, so to speak. From the responses, I get the impression that this is not really an issue in practice but that co-witnessing adds issues all its own.

The reason that I'm following this thread is that I recently got my mitts on an Aimpoint M2 and need to decide on the type of upper (flat top or A2) and sight arrangement that I'm going to put under it.

 

[mmike87]

I use a Yankee Hill flip up rear BUIS and it works great. I use the standard fixed front site. I find that the front site disappears when the rear site is folded down and I am using the Aimpoint.

http://www.yankeehillmachine.com/store/sights.html

The YH products are pretty reasonably priced, too.

 

[modifiedbrowning]

I have the YHM as well. I am happy with it, but I have only had it for a short time.
Here's some places that have good prices on the YHM.
www.rainierarms.com
www.eaglefirearms.net

 

[Grunt]

I prefer the Matech BUIS. Not only because it's what we have on our M-4's in the armoury so ti's nice to havea similar system on my M-4gery, but they have both windage and range elevation adjustments rather than just windage only like a lot of other models. Knights also makes a BUIS with range elevation and I think the one by Wilson Combat is also adjustable for elevation yet all of these sights fold down flat out of the way.
So why's it important to have a BUIS that can be adjusted out to say 600 meters? Well, look at your average Aimpoint or Trijicon red dot sight. In both of these cases you are looking at a 4MOA dot (granted you can get a 1MOA dot in the EOTech sight) that cover a 4 inch area of the target at 100 meters. Now at 200 meters, you are covering 8 inches and so on. Before long, you can get your dot covering more of your target that you're going to like and it's going to effect your accuracy. At longer ranges, a flip-up rear sight that you can dial in and use like any other iron sight is a better option IMHO.

 

[usp_fan]

Another happy user of the YHM unit.

--usp_fan

 

[Bartholomew Roberts]

Well, one problem for me with the Knight's 600m (haven't used the Matech; but if it is single aperture it likely has the same problem) is that the smaller aperture cuts down light transmission enough that in low-light scenarios you may not be able to make out the target or front sight.

IIRC, the front sight post covers something like 19MOA, so I don't know that I agree with the argument that it is a better solution at distance than a 4MOA dot. Sure you will have trouble with the dot on targets smaller than the dot; but you'll have trouble with irons too.

I like a same-plane dual aperture in a sight with no elevation adjustment. I can set that sight for an IBZ and cover to 300yds adequately. The dual aperture gives me a smaller aperture for precision and a larger one for movement/low-light. I have owned both the ARMS #40 and the Troy. I like the Troy better out of the two. The machining is better on the Troy, the windage wheel locks down, and the sight is absolutely motionless when locked out. The ARMS deploys faster but the spring-loaded mechanism that allows it to deploy quickly also allows barricades and crud to impede deployment of the sight. Either one will do the job though and the ARMS is cheaper... just be sure to loctite and witness mark the lock nut on the ARMS or you'll lose it from vibration eventually.

 

[Mute]

Folding BUIS - Troy
Fixed BUIS - Larue

 

[Grunt]

Uh, you don't cover the target with the front sight post. You set yoru dope so the rounds impact at the center of the tip right along the top edge. If iron sights were a problem in that regard, we would have been in a lot of trouble at the 500 meter line on the KD course!