6BR case capacities. Norma VS Lapua

[TAJ45]

I did a semi accurate comparison using Varget, shoulda broke out a ball powder. Late and didn't cross my mind. Tossing the high and lows out of a, yes I know, statistically insufficient # of samples, the wgts did clump pretty well with 3 grains diff. The Lapua w most capacity.

My question is: To shift to the Norma, how far should I back off my load of 30.2 of Varget, slight kiss, 450s and 107 Sierras Neck tension is STD non bushing.
Yes I'm running short on time for development.

 

[WyleWD]

'We've been using the Norma brass and the Lapua brass for the last couple of years in 12 Twist, 10 twist, and 9 twist barrels. We've been shooting 68, 80, 90, and 95gr bullets using several different powders. When we switch only the brass we've only on rare occasion had to tweak the load at all. On the rare occasion that we do, it is probably because I turned the necks differently on one or the other in order to clean them up. We've seen No difference in accuracy from one to the other. Your load and rifle are quite different than ours so proceed with caution. YMMV. and all the other disclaimers. JME. WD