I have three guns that I am going to reload for. .338 Lapua, .300win mag, and .308 what powder would be good for all three? Is there one?. I have been loading my .338 with IMR 7828 and I can hit at 500 yards. I am wondering because I want to go to retumbo but I don't see any loads for retumbo in 308 in any of my books. I have heard a lot of good things about retumbo that is why I bring it up. But I am open to suggestions.