I had read the ACOG's ambient light used for the daytime reticle can glow too much, causing difficult fine sighting.  Yesterday, in very full sun, while bench sighting and testing my new RRA M4 I did an old trick I used to do on heavy kicking rifles.  Being right handed I would lightly place my left hand on top of the scope to keep the rifle from jumping off the front rest.  Well, Inadvertantly, I did the same and the by partially covering the ambient light collection tube on top of the ACOG I was able to adjust the amount of glow from the amber triangle from my new 47-2 compact ACOG.  It made it much easier to use the 0 MOA aiming point at the top of the triangle with the extra glow that causes a 2nd, false, aiming point.

Big Al

Have known three gun match shooter to tape the fiber optics for a match.

Has anyone ever tried the opposite- to brighten up the fiber optic at night?  In my opinion, the tritium doesn't cut it in urban environments.  

I know they came out with a Reflex that you can put a baby Cyalume lightstick in, I wonder if there's a way to tape one up top (as long as you can hide the glow from the outside).  What's that special tape that movie crews use to tape down cables and wires- It looks like duct tape but doesn't leave sticky residue after.    

I've used bicycle tire inner tube to attach a cyalume sticks to a Compact ACOG at night. No sticky residue, and it doesn't glow. I think it would be difficult to do this with a full sized ACOG.

Steve.

Gaffer's Tape.