So I have tried the search function and nothing came up.  I also scanned the first few pages of the AR 15 optics forum and nothing.  I have also consulted the great Google oracle and haven't found my answer, I do apologize if this has been asked before (I am sure it has been but I can't find it).  I got a Colt LE 6920 about a year ago because I always wanted a Colt AR.  I have a number of them ranging from home builds to factory produced, but I wanted a stock Colt, don't know why but I did (I love it by the way).  It has a flat top receiver and the "F" stamped standard front sight base.  I have attached a detachable carry handle on the flat top pic rail and use this as my rear sight (again I really like it, and yes I have lots of red dots and optics but I really like irons as well).  The carry handle has a hole in the top of it (where you would carry it) but no hole in the bottom (where it attaches to the pic rail).  I know the hole in the top is to allow the attachment of an optic with a screw but there is no hole in the bottom to run a wrench through and there is so little room between the base and bottom of the handle I can't get an allen wrench in there.  My ACOG base is even angled to fit into the top of the carry handle. How do you attach the optic to the top of it?  This may be a dumb question and I own lots of Ar's and have built more than a few, just never run into this issue and I can't find anything on the net.  Thanks a million in advance for the help. 

attach optic to base

attach base to carry handle

wait, is this for an ACOG?

if you're using a hex-head bolt, just use a ball-end wrench

I can't, there isn't enough room to get a wrench in the space between the top of bottom of the handle and the bottom of the handle part, even the small portion of an allen wrench.  I could drill through the bottom of the carry handle so that I could get an allen through the bottom and top holes to screw the optic to the handle.  But there has to be a way, I have to b missing something here.

ball-end allen wrench

I see, didn't get you the first time.  I will try that, thank you.  Seems odd that that is the only way to attach (with a ball end wrench).  Thanks again I will try it.

I hope it works out brother

Easiest answer for me was to just cut off an allen wrench to fit, not like I didn't have any spares, it' a pretty low cost tool.

Grind the short end of the appropriate size hex wrench down for clearance,  or go to a good hardware store and get the right size conventional hex headed bolt and washer.

Detachable handles are not designed for optics mounting.  They are of different dimensions than A1/A2 handles.  No mount that I've seen will work with them.

the vast majority of ACOG sights are specifically (and originally) designed to directly mount to the carry handle (even detachable ones) using a TA30 washer and screw set

if it was up to me, I'd just mount it to the top of the upper receiver.  but it's not my rifle; it's his rifle, his question, and it's his decision

Ok.  I can say for certain that the old-school swan mount that puts a RDS in the "scout" position on A2 handles does not work with a DCH.  For all other mounts, YMMV.

I would buy Trijicon's TA51 base. Used or new take-off models can be had for under $50. It will mount the ACOG at 1.5" above the rail, the same height that your irons are now.

IMO scopes mounted on the carry handle are way too high for precision use. It's impossible to get a good cheek weld when you mount them there.

An ACOG is no small investment and a $50.00 mount that works is money well spent.

Aimpoint gooseneck mount on A2 detachable handle is gtg. Mine bolts up tight.