Thought ya'll might find this semi interesting. I was gonna use some Win brass in 270 WSM to work up some loads since I didn't want to wear out my Norma brass. so I thought I better do a water weight comparision to see how much difference there was in capacity.
I weighed 20 of each and the results were more than I anticipated.

avg water weight for the Norma was 77.2gr of water
avg water weight for the Winchester was 80gr of water.

also interesting was the spread on the two. the Win brass varied from 78.7 to 80.4, (1.7gr) the Norma varied from 76.9 to 77.9.(1.0gr) doesn't sound like much but it amounts to double the variation from highest to lowest.