I thought of it as well as even the 6.5 jap but when he mentioned "cheaper to shoot".. I discounted it.
Powder and brass being the most expensive variables in your reloads, I disagree. Swede brass is about the cheapest brass available from Lapua and the Swede case is more efficient than the overbore Norma or Weatherby. I like to shoot my rifles a lot, so I stay away from the ultra fast overbore gas hogs. Barrell life suffers when your start eveyr pill at 3000fps or more. Don't get me wrong, it's fun but I'd spend way more money at the gunsmith's shop rebarrelling and less at the reloading store.
a 6.5x57AI is a snap to build, and they will push a 140 grain bullet out to 2900+fps. Should be very accurate, as it's not an over bore cartridge. Dies are just as easy. You use a .257AI bushing die, and run the chamber reamer thru the Forster seater sleeve. Forster also sells a complete .257AI die set, but wouldn't go that way.