Yes that is what I stated, pressure up-velocity up. My thought is dacron is doing something similar too BPI buffer but without all the friction in case transition from body to neck. I think it is sealing the bore, kind of a gas check under the gas check. Testing dacron with a powder that proves to be not position sensitive in the loading density and case tested should be proof, my thinking anyhow? If 15 grains of Unique gives 1500 fps in muzzle up-muzzle down position in 8mm case with xx weight bullet, then add 1 grain of dacron and get a 100 fps increase, where did that increase come from if it's only job is to position powder? If it is not decreasing case capacity, not increasing burn rate by friction inside the case then where is the velocity coming from? Better seal to bore