I have shot 777 always and never used loose powder. In reading the reviews on the internet and the fact that I ran out of pellets last fall, I bought some Blackhorn 209 powder. I have a tube that has measuring marks on the side of it and I filled it up to the 100gr mark and then weighed it on my scale which showed me 74.8 grains of powder. I would assume that I should come up with the amount needed by weight and then mark the tube for my true 100grains (weighted). Correct?