I have a K-Kale 1940 Turkish Mauser that I plan to rebarrel. I can't decide what chambering I want. As tis rifle is a large ring, small shank format, that limits the pre-chambered barrels I can choose from. I have narrowed my choices to 6.5x55 Swede, .257 Roberts, and 7x57. This would be a dedicated cast gun. Of those three, what would you choose?