I believe Dan Coonan makes an inch receiver which is available from
FAC. If you decide to change it out, I may be interested in taking the CAI receiver off your hands. I have not seen one of the new ones. Entreprise is pretty proud of their inch receiver and price it accordingly. There are many FAL builders who can help you out:
Meeper - mailto:horsepowerfarm@pcu.net
Jayson Cotter
Both of these guys are quite reasonable and have pretty quick turnarounds. If you were in my neck of the woods, I'd tell you to bring it over to my house and we'd change out the receiver. I have all the tools.