What is the best brass for the 280 Ackley

[Tnwhip]

I have been useing 270Win. because it is cheeper than 280 brass. I have also read some where that 270 brass is stronger than 280. I find that hard to believe when the only different is neck size. I have also used Nosler 280 Ackley brass but I still have to expand the neck to 30 cal. then down to 7mm. because my chamber is the old original Ackley chamber not the new Saami. The Noslers are to short so I still have to fire form. What is everyone useing?