I was bored, so I decided to weigh my .300 WSM
Winchester Supreme Nickle Brass. This brass was necked sized, trimed and deburred. Found five that weighed about 4 gains lighter than the norm. I set these off to the side. Took the rest and randomly picked out six, placed a spent primer in and weighed the brass. Then I filled the cases up with distilled water and weighed again. Subtracted the difference to see what the volume of the case are. They averaged 81.4 gains of H2O. Decided to to the same to the five lite cases. End result was about the same, not enough to be concerned about.
Volume of case is more important than weight of case.