Hahaha, ok troops, after about 3 very quick IM's saying forget the pics and just say what the heck it is... I'll tell you.
Jay from Knights had an Aimpoint mounted in front of a TAO1nsn. I saw it and was like WTF?! I checked it out and you know what... It was almost just like a TA31. I was very impressed. We talked about it just for a second. I was wondering how large the apperature was through the 4x. And while I cant tell you just how big it was... I can tyell you the math doesnt work out. For example, IIRC, the Aimpoint M2 dot is 4moa. If you 4x that, it wouold have made it 16moa. There is no way in heck that it was that large.
It was very usable. It gave the TAO1nsn the BAC and it worked just like any other BAC model ACOG. I have since done up my Knights gun like this. It was easy having all the parts I needed on hand. Jay had a FF RAS on his gun. The TAO1nsn used the standard Trijicon TA51 mount. The Aimpoint was using the Knights Cantilever mount. On his, as I recall, the Aimpoint was pretty much right up against the ACOG.
I tried to mount mine like this but I couldnt. I was using a RAS 2 and the hump was getting in the way. First I tried just using a ARMS #22M68 mount without a spacer right on the hump. No good, you need to put the Aimpoint out further. I tired to mount it on a GG&G Cantilever mount backwards so the mount attached to the rails out on the handgaurd but put the Aimpoint right in front of the TAO1nsn. This worked well at first, but I ran into some problems. Mounting the Aimpoint on a backwards GG&G mount wouldnt fit. Somehow or another the battery cap kept getting in the way of the mount. When I tried to rotate the Aimpoint in the ring so it would clear, I had trouble adjusting the dot to a propper zero. Scratch the backward cantilever. In the end, I put the spacer on the #22M68 and tried to back it up as far as I could. This worked ok and is what I went with in the end. There is some space between the ACOG and Aimpoint, but I havent been able to notice it in my brief goofing around.
Advantages to this set up...
There is no "black-out" of the reitcle. The battery powered Aimpoint can be set to glow as bright or as dim as you need and is not dependant upon ambient light or the lack of ambient light to illuminate the reticle.
You get the BAC but retain the precise TAO1 sereis reticle. If you are doing a mix of close and long range shooting, leave the Aimpoint on. If you are just doing some longer range shots, turn the Aimpoint off and use the ACOG only.
For those who use NVD's on their AR's, it seems like all you do is remove the ACOG. The Aimpoint stays in the same spot as it would when used with NVD's.
Disadvantages of the system.
Well, it adds weight. You now have two optics on your rifle. While I sort of think it looks kind of cool, it also creates some clutter.
You are now somewhat dependant upon batteries. While its true you will always have your ACOG going, and the Aimpoint has mega battery life... well, you know.
You do have to turn the Aimpont on. BAC ACOGs are always on and ready to go. It is true that Aimponts can be turned on very quickly, and in fact, left on if need be. But not having to turn something on is always better than not having to.
I tried this same thing with the EoTech. I dont know... if you are a bog fan of the circle/dot reticle, you may like it. I seem to preffer the single dot of the Aimpoint, maybe thats whay I didnt like the EoTech all that much. But it does work. I'll post pictures of the set up when I can.