I think that this whole weapon is an Air-Soft copy of a special built USMC Carbine we (KAC) had on display at the last two Shot Shows.
First off, the screw holding the 300-M BUIS on is one I have never seen, we have been using a special wide (penny-dime size) slotted machine srew for this sight for over 6 years. The only other one we used was a button head hex head. What you see in the picture above is some else's miniuature version of the design of the ACOG scope mount nuts.
The Optima rig on the ACOG was our original idea, but until very recently, was not produced in any numbers. It usually shows up in photos of our guns, and of couse this photo above really looks like one-but its not.
Firstly, the ACOG pictured is too new looking, as the one we have been using for over 6 years is all dinged-up. It also does not have the filter thing installed in the objective.
Secondly, the little red-dot on our gun does not say "Optima", as we got ours from FirePoint.
So what we have here is what very creative people in Japan can do with some good gun photographs. I mean right down to the Marine Corps logo I ahd lazed on this receiver!
If you have not seen what is being made in toy guns and accessories, get a copy of the Japanese magazine "COMBAT". It will blow you away.
The latest copy (2003 May), has a Shot Show spread, Pictures of Mr. AK47 Kalashnikov firing my SR-25 at the demo we did in February, pics of the KAC wps collection, a whole platoon of Marines with M5 RAS / M16A4's with ACOG's fam-firing in Iraq, even some "skin".
Unfortunately, I can't advise you where to get a copy, as the publisher sent me one from Japan because my picuture is in it, and the whole thing is in Japanese.