I have a chance to pick up at a very good price a new M1 Garand receiver. It is listed as a IAI receiver made by Caspian. I have never heard of this receiver before, but I am very familiar with Caspian's frames for a 1911. They are an investment cast frame and the casting is done at Pinetree Castings which is a subsidiary of Ruger. Anyone have any experience with one of these receivers?