UPDATED: 8/4/2006


What is BUIS anyway?
BUIS, or Back Up Iron Sights, come in many configurations. The purpose of a BUIS sytem is to give the shooter the ability to accurately aim the rifle if the primary optic fails.

What types are available?
Two types are available, flip up and fixed. It is possible to combine the two systems and use a flip up in the rear and a fixed FSB (front sight base) or vise versa.

What is co-witness?
A: Co-Witness is the ability of your irons to look through your optic (1x - not magnified) - so they both shoot on the same trajectory. There are two kinds - absolute (both the dot and irons are on the same plan), and offset (where the irons are usually in the lower 1/3 of the optics display). With co-witnessed sights you can verify the zero of the optic by looking through the irons (the dot should sit on top of the front sight). However, normally you look over the irons and just use the optic (trust me, you won't notice the iron sights); should the batteries fail your head comes down a fraction of an inch and you're using the iron sights (looking throught the now-dead optic).
(from the Maryland AR15 Shooters FAQ)
groups.msn.com/isapi/fetch.dll?action=MyPhotos_GetPubPhoto&PhotoID=nJwAAANwMUuAJ7JC8BIu3u5hfwsqH9Z0x3oIwsknAVfVqkoJ0B820UgDvJdctqwwGbFtqpVZEnbk

What makes folding BUIS so good?
Some shooters like to use a primary optic (such as an Aimpoint or EOTech) with no visual distractions. The folding BUIS sytems would be ideal for this. Other shooters using magnified optics will require a folding rear sight in order to get proper placement of a scope. Many first responders like a folding front BUIS because it is less likely to get hung on something compared to a fixed FSB.

What makes fixed BUIS so good?
First, it is less expensive. Most rifles will come with iron sights and adding a primary optic to an existing system would be the cheapest way to get set up. Also, if you ever need your BUIS, there is nothing to "flip". They are already in place. That means that the time to transition to BUIS from a disapearing red dot is zero.

If I use a magnified optic, won't the FSB be in the way?
Nope. You won't even see it.

What distance should I zero my BUIS?
50 yard IBZ

Where is the best place to buy my BUIS? Who has the best prices?
Please support the dealers who support this site! Check the Industry Forum for a list of dealers and also check the Equipment Exchange for other deals on BUIS and optics from dealers and members of AR15.com!! All of the BUIS below have a hot link to the original manufacturer. These links are for informational purposes. Most of the time, an AR15.com dealer will have a better price. However, there are exceptions. Ameetec, Bushmaster, & Cavarms are all AR15.com supporters, so it's ok to order from them.
Talon Arms is my personal dealer of choice...
Talon Arms in the Industry Forum

What BUIS sytems are available?
ARMS
40L




40L SP (same plane aperture)



40A2 (2.0 oz)




Ameetec Arms
Front Folding

Rear Folding


Bushmaster BMAS
BMAS fixed rear (3.2 oz)

BMAS flip up rear (1.5oz)

BMAS Flip up front

BMAS flip up front rail mount



Cavalry Arms
Cavarms fixed rear



DPMS
Fixed rear

Mangonel Front Flip Up Sight

Mangonel Rear Flip Up Sight

Detachable Front Sight


GG&G
MAD flip up rear

A2 flip up

Tactical Modular flip up front

Flip up front for dovetailed gas blocks


Knight's Armament (no link available)
Rear Folding 300 Meter Sight

600 Meter Folding Rear Sight (2.25oz)

Folding Front Sight for RAS


LaRue Tactical
Fixed rear sight (QD) (3.0oz)


Les Baer
Front flip up w/gas block



LMT
Fixed rear sight

Tactical Front Sight Assembly



Matech No link
Folding rear
no photo

Midwest Industries
Folding Rear



PRI
Front flip up gas block


Rail mounted front sight



Samson Mfg. Quick Flip Sights


Barrel mounted Quick Flip Sight / Gas Block


Rail Mounted Quick Flip Sight


Weaver gas block mounted Quick Flip Sight






Troy Industries
Flip up Rear (1.9oz)

Flip up front Rail mount (2.2oz)


Wilson Combat
Flip-Up Rear Sight



Yankee Hill Machine
Gas Block Front Flip Sight

Forearm Front Flip Sight

Solid Front Sight

Front Sight Gas Block

Front Sight Tower

Flip Rear Site

Solid Rear Sight

BTT for comments anyone?

I would really like to see some opinions of people that have used or are using any of these BUIS.

Originally Posted By Perfectforce: I would really like to see some opinions of people that have used or are using any of these BUIS.

That's why I posted this. I was hoping that we could start a central BUIS discussion thread instead of reading 50 seperate threads on each individual BUIS.

FWIW, I use the ARMS 40A. It's very solid and combat proven. You can find them in the EE all the time for less than $100.
I am looking to pick up a new BUIS for a scoped upper. I really like what I am hearing about the ARMS 40L and the Troy folder. Hopefully we will get some reviews soon.

This rates a permanent tack.

Dave S

BTW, thanx.

DPMS, LMT and Les Baer added

Nice job Strick909!

You might want to throw this into the mix as well: CNC Gunsmithing A1 BUIS

Good info. Now, just add the weights for each, and it will be tack worthy.

Great thread!!!!!!

+1 for Tagged.

tag

Originally Posted By Corporal_Chaos: Good info. Now, just add the weights for each, and it will be tack worthy.

If someone knows the weights of each, I will add them. And does anyone have a link to Knight's?

I did not list MSRP because all of the links are hot and you can get that info from the manufacturer anyway. But, if you guys want it, I will list it. Is there anything else I am missing?
(BTW, I did not list the A1 hot-linked because it is not yet a regular production sight.)

Knights (via Impact Guns), Cavarms, and Wilson Combat added to the first post.

Good info. Now, just add the weights for each, .

I'll tell you what I'll share the info I have if you get the weights on the others:

From the 'Chart of AR-15 Part and Assembly Weights' from The Maryland AR-15 Shooters Site:
(weight is in US ounces).

Troy Front Flip Up Sight 2.2
Troy Flip Up Rear BUIS 1.9
ARMS #40 BUIS 2.0
LaRue BUIS 3.0
KAC 600M BUIS 2.25
Armalite "Chopped Carry Handle" sight 4.9
Detachable Carry Handle (A2 sights) 9.6