Is this a needed step with Lapua .338 LM brass to obtain max accuracy / consistancy? I haven't sectioned a case but the flash hole sure does look burr free from peeking in there with a light. Also, just for fun I weighed the water content of Norma and Lapua .338 LM brass vs. RP 300 RUM brass. They were virtually identical. 113 grains for for the .338 LM and 113.3 for the 300 RUM. Sadly, finding good 300 RUM brass is difficult.