I already knew that point. That was not the question I was asking so I didn't care. I wanted to know the starting point for a M1A that would be below where the gun works. That was all I wanted. I can manage the rest on my own for now. This is a learning process for me but that is all I need/wanted at this time. Trying to avoid too many trips to the range and too many test bullets that are wasted primers and powder.