I'm just wondering, no intention of starting anything here, but I'm curious - where did you get the info that he carried an Aimpoint? I know it may very well be trivial stuff, but I own the book BHD and saw no mention of that in there.
Saw references to it on History Channel documentary about the battle, also read it in first hand accounts of the incident written by soldiers who were there. (I will see if I can dig up that link for you
Anyway,...the original request by Viking was for a rifle like the one he used in the movie...(which was indeed, an M21 with an Aimpoint site)