A friend who personally builds his own long range hunting rifles, and seems to favor wildcats, has had good results with a .300 Weatherby, necked to 7mm. Because he hunts in California, and no lead bullets are required, he has worked up an accurate load, using 168 grain bullets, and RL 25 (I think). In the last few weeks he as been evaluating many of the suitable powders, and this is the one that he settled on. He shoots short range benchrest, and is a skilled gunsmith, shooter, and reloader, and he knows how to work up and test loads. One of the main criteria that he has for case design, beyond capacity, is that a case be nearly full with powder. This results in better extreme spreads in velocity.
Another friend, who has done a lot of out of state elk hunting at long range, started out with a .338-.378 KT (for his first rifle built specifically for that application), and found that it drove bullets faster than their design velocities, and that when he tuned down to the velocities that were matched to bullet construction, that his cases were not as full as he would have liked, so he had a switch barrel rifle built on a slightly modified .338 Lapua case, that has a 37 degree shoulder, in both .338 and .30 calibers. While both shoot very accurately, the .338 took less effort to find a good load. He has shot under a quarter inch at 100 yards (5 shots) with that monster, which is as much a tribute to his shooting skill as to the caliber and rifle.
