What is the best option for a rear sight on an A3 upper?

Looking for something comparable to the A2 sight but I don't want the carring handle.  I'm going to add this on a carbine and want to keep the weight to a minimum.

What type of rear sight is mounted in this picture?

[IMG]http://webpages.charter.net/lousar/pictures/DSC00006.jpg[/IMG]

That's an ARMS #40 folding sight - weighs almost nothing.
[url]http://www.armsmounts.com/list.html#40[/url]-------------------
And another option--------
[url]http://www.dpmsinc.com/10Expand.asp?ProductCode=FT-RS[/url]

[img]http://www.dpmsinc.com/Products/FT-RS.jpg[/img]

What type of optic do you plan on using, if any?

If you are using a regular scope:

A chopped carry handle is the best option.  Basically, just use a hacksaw to cut the handle part of the detachable carry handle and leaving the sight.

Crane makes a sight that is the closest to the carry handle/A2 sight but it is heavy and a bit expensive.

DPMS and Yankee Hill (sold by Bushmaster) each make a detachable rear sight that has the elevation wheel and doesn't flip down.  These are similar to an A2 or carry handle in operation but neither is quite there.  The Yankee Hill sight is a little farther forward than others so the sight picture is close but not identical.  The DPMS is in the right position but they don't have the full range of elevation, both of mine only go to 5.  The DPMS has also had some durability issues with the attachment screws.

If you want to use a scope then you'll need a sight that flips down out of the way.

GG&G and ARMS make flip-up sights with the same sight picture as an A2 but the flip-up prevents the elevation adjustments.  

GG&G, ARMS, KAC and others make other designs of flip-up sights.

I have a Kobra Holo sight I'll probably be using at first.  Even if I upgrade it will be a holo or some type of red dot.

The ARMS #40 looks ideal.  Any cons on this sight?

Anybody know if the DPMS detacable sight will fit with a SIRS ? Like the ARMS #40

No, they won't.

I vote for the ARMS #40.

Joe

For light weight and flip up convenience, ARMS #40.  A cut carry handle is the best option in a fixed BUIS.  I also like the GG&G MAD, but not many others seem to.

I stuck an LMT sight on mine. As a general rule, I dislike A2 sights because the "play" between the sight base and the sight itself just doesn't inspire my confidence in its' ability to take a beating. All of the detachachable carry handles I've ever seen had a lot of this play, and I've shied away from them because of it. I saw MSTNs' ad for this sight though, and since WES thinks highly of it, I figured I'd take a chance on it. The LMT is made to tighter tolerances than the  detachable carry handles I've seen, and there is almost no "play" in it. Just for good measure, I also stuck an XS (formerly AO) same-plane aperture in it. For me, it was money well spent.
[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=16472[/img]

[url]http://mstn.biz/[/url]

My votes for the GG&G A2 buis. I like it because it is soild billet machined. Not cast.