Re: Which brass?
As a general rule, Win brass is pretty hard to beat unless you start paying for the premium stuff like Lapua, Nosler, or Norma (and I'm not sure I can shoot well enough to take advantage of the 'good stuff'). The only real advantage of the better brass is uniformity from one case to the next. I use Lapua in my very best rifles but I don't waste the money on lesser guns.
Remington is a name that usually doesn't come up very often when talking about the best brass, but every once in a while they will make a batch of nickle-plated .223 that is excellent - it even has the flash holes deburred from the factory. I bought 1,000 rounds of that stuff a few years ago and it will hold its own against anything else I've tried (and I've tried all the best brands in that caliber, even the exorbitantly priced Norma). To be fair to Remington, I've seen several articles recently that said they are taking some serious steps toward making their brass a much higher quality.
Whatever brand you choose, I'd buy as much as I could at a time. Even brass from the same company will have variations from one lot to the next. Eliminating sources of inconsistency is the name of the game when it comes to accuracy.