I'm thinking about building a 338-06 very accurate 0-500 yard Thumper gun. The 338 has so many bullet options it seems like the best idea. The gun must be able to shoot 3/4" Moa at 200 yards or less. But I want to be able to reach out and kill a Grizzly or Big Russian boar out to 500 yards accurately. Also, if I'm stalking and run into either to drop it dead at 50 yards or less. I'd expect to have 2 loads with me, probably 1 in mag for a the 0-50 yard stumble into a big beast and maybe another for the longer shot to 500 yards. Probably iron sights and then a quick attachable scope. I plan to carry 2 magazines , one for the short range and the other out to 500 yards. Any ideas here, 338-06 fit the bill? Barrel length not exceeding 24" and carrying weight under 10lbs, allweather. Also, what twist rate. Any thoughts welcomed, even a different caliber.