Ron;

Per comments of HeymSR20 above: What is the thickness of the monobloc at the breech end. If my calculations are correct the 6.5x 57R cartridge chamber diameter at the base is about .470" and your barrel stub OD is .626" leaving you wall thickness of .156" at the breech. With the monobloc under compression with the shrink fit, are you depending upon the monobloc to add strength to compensate for the lack of substantial wall thickness for the cartridge dimensions? Additionally, are you planning on the typical 48,000 or so psi for loading the 6.5x 57R?