If you only shoot factory I kinda lean to the 243, but if you handload its a diff ball game. I get over 3100fps with a 100gr bullet and dang near 3000 with a 115gr out of a 22" barrel in the 257. Most 243 100gr factory loads are getting around 2900 in standard barrels with some being a lot slower. There are some good bob factory loads as well, like the Hornady light mag and other +p loads. Me for one I just love the case in the 6mm,257 and 7x57. And you can not go wrong with the 6.5x55,260, 7x57 or 7mm08.