I just did a Google search on "calculate load density" and the first thing that popped up was a discussion on another forum that contained several methods of doing this. There is also software that will do this for you, such as "QuickLOAD" which is reviewed on 6mmBR.com. It will suggest which powders give the highest load density, which saves you from buying ones that wouldn't work out. John Barsness seems to like that one as he mentions it in his articles. None of this stuff is exact, because case volumes vary and powder varies by lot. However, it will get you close. I own two 6 BR's but have not paid much attention to load density as yet. In my 30 BR 36 grains of Benchmark fills the case to the base of the bullet and a scooch more and gives excellent accuracy. This powder seems to have some bulk, but I have not yet tried it in the 6mm BR. I am thinking of buying QuickLOAD. I think the closer you get to a full case, the less the powder will settle when the round is chambered, therefore more consistent results. I cannot state this authoritatively, but I suspect that you might not notice much difference between 93 and 97 percent, but 86 percent wouldn't be so good. I subscribe to Loaddata.com from Handloader magazine. It indicates that H322 or VV-N133 might be good choices for you, but it doesn't reference load densities. I would suggest trying 80 grain Berger flat base bullets in your 12 inch twist for 200 yards and under. It might buck wind better than the 68-70 grain bullets.
