I recently chronoed some 6PPC loads with Lapua and Sako brass, using the same load and found that the Lapua brass gave inferior MV by about 59fps on average compared to the Sako. The load was 26gn of VV N130. I am fairly sure the Lapua brass has a slightly higher capacity. Could it be that the Lapua brass generates less pressure hence the lower velocity? Just an interesting quirk I thought I'd put up. Incedently I haven't noticed a great difference in accuracy, if anything the Sako brass does better even though it's weight varies more and the individual cases ay have a different number of previous firings.