Welcome to 308. It's my favorite cartridge and if you do it right, you won't need anything else.
I've played around a lot in the last couple years. So far, the most accurate powder has been benchmark, but it's too fast for anything and pressures out before you get good velocity. IMR 8208 XBR is also very accurate and you can get reasonable velocity, but ultimately it's still too fast for anything but lighter bullets. AR-Comp has been amazing for wringing velocity out of the cartridge--I mean better than varget or anything else I've tried, and for every projectile I've tried so far. Unfortunately, I haven't yet found the accuracy for the AR-COMP that I found with benchmark and 8208 XBR.
For projectiles, the 137 gr hammer hunters that everyone on this forum is obsessed with have been good. Easy to reload and consistently accurate. 165 gr Partitions are amazing and I trust them to kill more than the hammer hunters, but I don't trust them for accuracy as much as the hammer hunters. I'm experimenting with the new tipped hammer hunters (HHT, 138 gr) right now and so far so good. I'll probably switch over to them for whitetail this season. The most accurate projectile I've shot has been a 178 grain ELDX, surprisingly, which makes me think my barrel just likes heavier bullets. Unfortunately, my main 308 is 16 inches and I haven't figured out how to get enough velocity with those heavy bullets to really dedicate them for hunting.
For brass I use Lapua. I tried the alpha brass and while it is super uniform and seems to be a bit better in quality than the Lapua, I get more pressure signs with it. Might be because it's softer and just shows the swipes more, or I'm actually getting more pressure with it, I don't know. In either event, I don't like thinking too much about it so I stick with Lapua now.
My best load has been 137 gr hammer hunters with IMR 8202 XBR. Start low and work up
