Getting brass can be a pain. It took me 10 months to get 500 Peterson 280AI brass in one lot. That should do for a 6mm/280AI cartridge rifle I having built. You can rechamber the barrel, and shorten the barrel at both ends and continue to use the barrel. I for one pickup or take used brass, and store it for a rainy day. I agree that volume weight is the way to go. I think and maybe I am wrong, but you are weighting the contents in grains. Noting if there is a difference in volume weight between cases. It use to be you could go into any sporting good store and get brass or some type. Not now, and even ordering from a supplier takes time now. Some cases are not being made presently by the high end manufacture. I am not complaining, but that's life presently. Store your used brass and turn them into a recycler. They will pay in cash. I wouldn't go down there with 50 pieces of brass, but several 100 is a different story. I think everybody is rubber necking like me looking for components for reloading our rifles, pistol, and shotguns. Correct me where I am wrong.