Two of the favorite cartridges of those who were knowledgeable "gun people" until the mid-1950s were the .250-3000 and the .257 Roberts (basically the 7x57 case necked down). Both have unjustifiably submerged into obsolescence since the appearance of the .243. I have the dies to load both calibers, but no guns chambered in either. Maybe someday I'll run across a good deal on one. Now we have the 6.5 Creedmoor as a hot caliber. Very strange, as no other cartridge in 6.5mm has ever caught on in the USA. I guess it's because it works in the AR action.