The KAC 600 meter is a tough sight, but not really a CQB sight.  Seems that the current solution is to chop a carry handle and use the rear portion as a detachable A2 sight.  Not a fold-down however.

Perhaps there is not enough demand for such an animal to get a payback on the necessary design/engineering.  Folding sights are, or should be, back-up sights. Quick and simple to deploy, and out of the way when needed. Most applications would fall into three broad categories:

Iron sights primary (e.g. A2 carry handle)
CQB optic primary (e.g. Aimpoint M68)
Telescopic optic primary (e.g. TA01 NSN)

In the first, no backup needed (typically)
Second, no elevation "needed" to backup red dot
Third, designated for longer ranges typically, so a 200-600 BUIS would be consistent with the intended use.

While you can always make a case for another set of requirements for some particular situation, the above probably represents the general thinking behind BUIS design decisions.  I think that a sight that was compact, folded low, with dual apertures and elevation adjustment would sell well in the civilian market (high cool factor), it would not be a great choice for many military applications. It would be more complicated, more expensive, and little used in most situations.

It would be an engineering marvel though. Maybe someone will take the plunge and build one anyway!

Paul
MSTN

VERY WELL PUT! NEVER BEFORE HAS SUCH A WELL THOUGHT OUT SET OF REQUIREMENTS BEEN PUT FORTH THAT I HAVE SEEN. WE NEED TO PUT THIS EXPLANATION ON OUR WEB SITE!

UNTIL SUCH TIME AS THIS NEW ENGINEERING MASTERPIECE EMERGES, THE KAC 600-METER MICROMETER REAR SIGHT IS AS CLOSE TO AN ENGINEERING MARVEL AS I EXPECT WE WILL SEE. IT IS, AFTER ALL, WHAT IS USED ON THE KNIGHT'S MK 11 MOD 0 7.62X51 SNIPER RIFLE... WHICH NOW GUARDS THE C.I.C.

WES GRANT
M.S.T.N.

YES, IT HAS BEEN WET BUT IS GOING TO TURN OUT NICELY TODAY, THANKS.

ON SIGHTS, GO WITH PAUL'S ADVICE, ABOVE.

DO YOU HAVE AN AIMPOINT OR OTHER RED DOT TYPE CQB OPTIC AS PRIMARY? THEN BACK IT UP WITH A CHOPPED C/H OR GOOD BUIS. BUT KEEP IN MIND THAT YOU'LL SHOOT BETTER WITH AN AIMPOINT AT ANY RANGE THAN WITH ANY IRON SIGHT COMBO ON AN M4 WITH ITS SHORT SIGHT RADIUS!

IT'S PROBABLY BEST TO LET THE SNIPER TAKE ALL THE LONGER SHOTS, ANYWAY...

WES GRANT
M.S.T.N.

YOU'RE STILL STUCK WITH THE M4'S SHORT, SHORT, SHORT SIGHT RADIUS AND THE 14.5" BARREL'S RATHER ANEMIC PERFORMANCE AT THOSE RANGES. PLUS, I FIND THE ARMS #40 SMALL APERTURE TO BE LESS THAN EFFECTIVE, AT LEAST FOR MY EYES.

VERY FEW MORTALS ARE THREAT BEYOND ARM'S REACH. AT 200 YARDS, THOSE THAT ARE CAN KILL YOU BEFORE YOU SEE THEM. WITH THE M4 AND UNIT POWER OPTICS, THINK ARMS LENGTH TO 200 YARDS.

WES GRANT
MSTN.BIZ

BUT, I SHOULD ADD, THE KNIGHT'S 600-METER MICROMETER REAR REIGNS SUPREME AS A PRECISION SIGHT FOR A FULL LENGTH SIGHT RADIUS RIFLE LIKE THE SPR OR MK 11 MOD 0.

THAT'S WHY THEY USE THEM ON THE SPR-A/B AND MK 11.

WES GRANT
M.S.T.N.

ABSOLUTELY!!!

WES GRANT
M.S.T.N.