I'm new to using Lapua brass basically because the cartridges I have shot and reloaded for did not have Lapua brass available. So far I'm very impressed with it. I've got 6.5-284 to be necked down to 6mm and 223 Rem. A random sample of each showed less than .001 in length difference. Case mouths visually appear (is that redundant?) to be perfectly round. Pockets seem to be very square and uniform. No dents or apparent irregularities in 400 pieces of brass. I have deburred the flash holes, not sure if necessary. I have also squared and uniformed the pockets, not sure if necessary. I plan to load the 223 brass without sizing because it looks ready for loading and because I do not yet have a sizer for it. What do you do and don't do before you start seating bullets?