I'll second Tinker's findings with the .268 dia Carcano bullets in a 6.5 Mannlicher. Not worth the time. As I said, my carbine and most every other 6.5 European Military barrel I've ever checked was .268 or close to it, but the ammo was .264,,except the Carcano of course. Aside from them getting stuck in (my) seater die, they could, depending on your case neck dia., expand the neck dia. a bit too large for the chamber and cause problems. These Military Carcano bullets are .268 all the way down, unlike the commercial bullets Tinker had which had a .264 dia seating dia. section. You may need a slightly larger expander button for your die with these to better allow seating of the .268 bullet. Neck turning/reaming are options,, use of Carcano dies for neck sizing only...Lots of little things for usually no gain in accuracy, and perhaps a loss. The .264's shoot so well in my 1903 M/S (with it's .267" groove dia) and so far the early reports are that they will shoot well in the Steyr carbine as well, I have no intention to even try my hoard of .268's as is. I'll make up a simple push thru sizer to squeeze them down to .264 and spend a mind numbing couple of hours making them usable.
That is a great looking sporter Tinker. I have a Dutch 95 action that I'd like to barrel to either 6.5 or 303 and make up a sporter like that. More perfect lines I can't think of..Thanks for posting the pics..