The best is water with all cartridges in the same state (best is fired, but not resized so all match ones chamber dimensions). Weigh dry and then filled with soapy water. Soap or detergent will help eliminate a potential meniscus issue (i.e. water clinging either above or below the top of the cartridge neck). Degree of fill must be consistent. Determine water weight by difference and convert to volume.
I've personally gone to simply weighing once fired and then anal prepped brass.
Like said above, if your cartridges are pooled from mixed sources, I'd be inclined to dump and start from scratch.
Last edited by 1minute; 08/31/16.
