First off, I'm using Winchester brass with some cheap Remington large rifle primers I found. (already have 2 duds in 15...they suck) I am using Unique under toilet paper and a case full of COW up to the neck, then plugging it with paraffin wax. I started off at 10% of a full case load, only 3 grains. (not sure why only 30 grains Unique fit) Nothing at all happened at 3, at 4.5 I had a slight rounding of the shoulder, but the case wasn't much wider. 5 grains was about the same. I jumped up to 7 grains and it got better, looked like a Weatherby shoulder. Kept getting slightly better until 9 grains when it looked about fully formed. Going to 10 grains didn't do much more. Looks like the only way to get the final sharpening of the shoulder will be to fire with bullets.