Also, I think it's a good idea to keep track of how many times your brass has been reloaded/fired. Not only would I keep the brass separate for the individual gun but I'd keep the brass separated and into groups based on how many times each piece has been reloaded/fired. Say you have 25 pieces of new brass for each gun, don't reload a piece a second time until you've cycled all the way through them one time.
I know guys that'll use the same 10 or so pieces of brass to work up a load and they'll have no clue how many times those ten pieces were shot, then once they get the load they want they load up however many and mix those ten right in with the rest that are virgin brass or maybe only been shot once and can't figure out why their gun is all of a sudden shooting all over the place or some are tight and some aren't.