Originally Posted by
bob q
I have over 80 Carcanos and have never seen a .264 groove bore . Just how would you "tinker" with one to shrink it ? Wash it in hot water ? The early rifles had grooves as deep as .270 , they did tighten them up to close to .266 by the M-41 . The problem with the big Hornady bullet is to the groove size but the land , and the fact the bullet is made wrong . Way too thick a jacket . With a tight land the gain twist guns will have trouble engraving the bullet jacket as it goes down the bore and the twist changes . Way to much drag and the pressure goes up . With the tight groove .266 rifles with tight lands also , there is just not enough hole to push a bullet that has such a thick jacket that will not deform enough . They can be found with bore hole combinations that can work with the .268 bullet , or not . Hornady sells a good .264 160 round nose for the 6.5mm's and a .300 128 for the 7.35mm's . 6.5mm cases can be used for both . Also there is nothing wrong with a 8mm one [ in good shape and put together correctly other that the recoil ] as the Carcano action is a large ring with just as good as steel as the K-98k and two large front locking lugs .