Well, I didn't get any real GI cases weighed. I have a sack of LC out in the reloading shed but it's raining, etc, etc, whine, whine.
I did weigh some brass I had here in the house and it was pretty interesting. First off, all of the brass had primers in them. So the actual weight would be different but any variance between the cases would be pretty real.
BHA brass with a military primer crimp but a BHA head stamp: High 97.2grs, Low 94.3, variance, 2.9grs
BHA match: High 97.4grs, Low 95.4, V= 2.0grs
Lapua, standard head stamp, High 107.8grs, Low 105.9grs, V=1.9grs
(and now we get to the good stuff) Lapua Match High 96.5, Low 96.1 V=.4
All of this brass was 1x and had been re-sized, primed, and trimmed to length. I found the 10 gr difference between standard Lapua and match Lapua interesting. The sample size was 10 each.