RE: .338-06
I had one built in '97. I used a Remington 700 ADL and had a Kreiger barrel put on it. I love the gun, and it shoots better than I can. If I do my part, the gun will shoot under an inch at 200 yards. I just put a new scope on it - a 2.5-8X Vari-X III.
I have a set of Redding .338-06 dies, and resizing the cases is easy. In with .30-06; out with .338-06. No fire-forming necessary. I've used both Winchester and Remington brass casings without issue. I don't recommend nickel-plated brass, though. I tried some once-fired nickel casings, just for the heck of it, but I saw lots of cracks in the case necks.
I have found that IMR 4064 power works best with the different bullets I've tried. I have fantastic accuracy with Nosler 200gr Balistic Tips and 250gr Speer Grand Slams. One-hole groups at 100 yards. I am tinkering with Nolser Accubonds now, both 200 and 225 grainers. Results are promising, but not quite as good as the other bullets. Recoil isn't much different than an .30-06.
Unfortunately, I haven't had a lot experience with it on game animals. I whacked a black bear this spring with it, but that's it. I was very satisfied with the performance, though. Two shots with the 250gr Grand Slams - one shot took out both lungs, and the other clipped the top of the heart. The bear didn't make it 15 yards.