.264 Weatherby mag is a .257 weatherby mag case necked up to 6.5mm. Its a wildcat. also known as 6.5-.257 Weatherby. I just edited my post to make note of that. Ill admit that was kinda stupid to throw it in with all those commercialized cartridges. Ive never seen one in person but have read about them. Seems like a good idea to me but i guess Weatherby doesnt feel the same. I like alot of the Weatherby calibers but cant afford to shoot them. Here's a link to pac-nor barrels wildcat chamberings. They offer the 6.5-257 wby. in addition to another 6.5mm wildcat worth mentioning, the 6.5-06 ackley. There are alot of 6.5 wildcats floating around out there that deserve commercializing over the creedmore IMO
http://www.pac-nor.com/wildcat/