I've had excellent results so far in terms of velocity with IMR7828. I will be trying some AAMagPro on my next range trip. I have also had great results for accuracy with AA8700, but that's been discontinued and is near impossible to find. I will update with results from the range next week.
Brass is going to run you about $62 for 50pcs, or twice that for 100. There's just no getting around it, really. Of course, you'll be getting Norma brass for that price, and the inherent quality, so it's worth it, in many respects. If you find brass cheaper than $1 per piece, please let me know where!
Correction: I ordered a Mark V 270 wby for my wife and now she doesn't want it :x Wants something sparkly & says she'll just use my 30-378 cuz it doesn't kick with the brake and she can hit with it easily. NOt too cool since that is why I wanted to buy her a nice gun. To Keep her off mine!!
On the bright side I'm now obligated to buy something, lol. I have wanted a 338 rum for quite some time, might have to try that, or a VTR 15. At the moment the 375 ruger looks kinda interesting too, but the store isn't a ruger dealer. just tikka, sako, browning, remington & wby.