Daniel-
Almost all of these old brit mannlicher sporting rifles have oversized bores -- and shoot best with the .264 Hornady 6.5mm 160grSNRN
It might take a little adjustment for you to feel comfortable doing it, but load some of these up and shoot the rifle.
You'll likely be very surprised with how well they shoot.
Hornady also makes a .268 6.5 that they market for the carcano.
I'm pretty disappointed with this bullet, especially in the 6.5/53r and the 6.5/54mannlicher.
The bullet is almost completely cylindrical, not tapered like the .264 is and like the proper period round nose bullets were, which featured a long 'bore-riding' section in front of the cannelure, and a cylindrical .264 section behind the cannelure.
The .268 just didn't perform well at all in my Jeffery sporter. The rounds weren't accurate, the pressures were a pain to track, and didn't seem intuitive when compared to the chrono readings.
I've abandoned them in my load development.
I know quite a few guys who have gone down the same road.
I actually called the guys at Hornady one day last year, noting this unfortunate design problem, comparing it to it's 264 brother. The guy I was talking to didn't even know of this issue, so I asked him to set the phone reciever down for a minute, get a box of them and a micrometer, and get back on the phone with me. He was surprised that Hornady had done this with the carcano bullet. I don't expect them to revise the bullet forming dies any time soon, but I might call them again on this later in the year to see if they've done anything about it.
If your bore is *very nice* you might want to look at casting hard cast bullets for it. There are some very nice moulds available, and you can get a range of lubrisizer dies to experiment with while working up the perfect load for your rifle.
The bore of my rifle is a bit rough, so it's jacketed bullets for me. Tried the .268 and haven't looked back since.
Don't let that bore measurement be a dealbreaker for you.
Get some components and get it running.
And post some images of it for us to see!
Here's an image of my WJ Jeffery
A closeup of the banded bank of rear sights
--Tinker