If the bore is good, I'd run it as is with 280 brass (if indeed it's been cut to 280)

I wonder if it's not been chambered in 280, but the auction description is based on 280 brass found with the rifle that's been formed to 7x64 to work with the original chamber.

I have a nice old 7x64 here that was left with a bunch of 280 brass that had been formed as such.

What are the hurdles to getting a rifle from Canada imported into the US..?