This is very interesting, an excellent report and a good experiment. The part of it that is very interesting to me is that it confirms what I have done the velocities are a bit different but considering 5000 feet difference in sea level thats to be expected. The gap between 110 and 120 is the same on both powders. I believe that it is because thats the point where the pressure makes BH burn progressively with efficiency . Do you concur Mike?