I've loaded for several of them with a wide variety of bullets and the one powder that for whatever reason always seems to show the best accuracy, barrel cleanliness and great standard deviation is H-4350... I've tried slower, quicker and all the rest with just about every bullet made and it stands alone on the top of my list.. the same goes for the 300 SAUM, it's almost identical twin and I've also noticed that the hardly ever mentioned SAUM is one super accurate cartridge.. I don't know what it is about the design, their so close but it for me seems always just a little better with almost all the bullet types I try.. TWO GREAT CARTRIDGES, good for anything you'd care to blast with either......I wonder how sales have been with the WSM lately.. don't hear much about it, maybe it'll go the way of the rest of the short mag revolution.