Unfortunately, those are capacities full to the case mouth. Capacities with a bullet seated are much more useful.
Unfortunately, capacities with a bullet seated vary with bullet style, chamber throat, and magazine length (ie. seating depth). Since it's fairly straight forward to calculate the displacement of the seated bullet, all internal ballistics programs start with the capacity of the empty case, and the list in question was written for use with a Powley Computer.
For Quickload, is it more accurate to use usable volume or total volume?
For internal ballistics calculations, one needs the net (useable) case capacity. QuickLoad has a large database of bullet dimensions and will accurately compute the net capacity if you give it the case and cartridge lengths. If you've measured the net case capacity instead, you twiddle the seating depth in the software until you match your net capacity. Both ways give the same result (when the bullet dimensions are correct).
As for grains of water, there are 252.4 gn of water per cubic inch.
