I have a great 6.5x55 and a .257 Rob, but I don't own a .260. But if (like you) I did own a .260, and wanted to set up a rifle for my 11 year-old without buying any new components and dies, I'd make it a .260.
I'm kind of dumbfounded though by this apparent desire on your part to NOT get a new caliber. Come on, Man!
Cheers,
Rex
