M-S did make 6.5x55, there was one one Gunbroker about 15 yrs ago and one of the members of the Mannlicher Collectors Association had one, they were Model NO and stamped on the receiver ring Kal. 65x55, one was a full stock with a 24" barrel. There is also a pic of one on the Mannlichers for auction thread on this site. I guess if you were willing to pay and place an order Steyr would produce almost any caliber