I came across this photo which I thought was pretty interesting. The 82nd Airborne soldier is holding an M16A2, which at the time would have been quite new, having only been adopted by the Army three years prior. On top is an Armson OEG, I believe an original production model based on the flat faced sides on the front and rear, compared to the round shape of the Generation II models.
The occluded eye gunsights work on an occluded principle that requires both eyes to be open to be used. The view down the sight is pictured below.
A black backdrop with a red dot, illuminated by a combination of tritium and fiber optic. The eye not looking through the sight views the target, and the user's brain combines both inputs into a single image which overlays the dot on to the target.
This is meant for fast, close range shooting, as at distance the inherent inaccuracy becomes increasingly apparent. Using this type of sight takes practice to be able to do effectively, and even once practiced the sights become tiring on the eyes after extended periods.
The other unusual item in the picture is the 20 round straight magazine, as the 30 round magazines had been long adopted and in circulation by 1989 and the 82nd Airborne should have had ready access to them. The magazine may have been a personal preference.
