Quoted:
You might also notice the gas tube coming into the left side there.
The gas cut on the side was used in the AR-10 before the use of the gas key on top,in the image the carrier uses a carrier guide pice,it was used to aline it with the cam pin head and it also stoped the bolt assembky from rotating insidr thr receiver,this was also the funcion of the gas key,the carrier pice (and gas key) and the charging handle are the reason for the upper guide rail in the upper receiver(the guide rail in the side gas cut AR-10 is smaller then the one in the gas key AR-10).
The lack of a upper receiver guide rail in the prototype rifle make impossible for the use of a carrier guide pice and for the alignment of it with the cam pin head (the cam pin head cant be exposed out of the carrier as there is no space for it.What i am trying to find is the way for the mechanical operation and placement of parts with the prototype rifle,a photo of its bolt assembly is needed.
Thank you.