6.5 RPM is probably the closest factory offering but only weatherby/Hornady brass available. Sounds like the Sherman Max with ADG brass is a great option too But just a little less capacity and may need a medium action unless you're gonna use the 124s in it, but I'm not familiar with their length. The 6.5x68s or the improved variant, which I believe is called the 6.5 Boo Boo, with rws brass is would be cool, but uses an oddball .512 bolt face. The 7 Blaser Mag necked down and possibly improved would definitely get you there. It is beltless, would have slightly more capacity than the 264wm and with its 2.33 case length would have room for the longest bullets made in a standard 3.5" long action, and uses the standard .532 bolt face. Only issue there is finding a good supply of brass which I believe only Norma makes. I have seen it available at grafs but haven't checked lately.