I have a Remington 700 5R heavy-barreled .300 Winchester Magnum. It shoots quite accurately with several bullets, but these have all been 150-180 grains. In the last couple of weeks, I've done some preliminary work with the 200 grain Sierra GK and H4831SC powder. While I've struggled to get a muzzle velocity of 2800 fps, it appears that this bullet may be the most accurate hunting bullet tried so far. This is one of the few bullets I've ever used where seating depth made virtually no difference in accuracy.
Again, I've only done limited work, but it looks promising so far.
