I mostly use military .40 S&W brass for making the .44 caliber bullets. It's very consistant in weight for one thing, and for another, there is so much .40 S&W brass on our range that most of it ends up at the scrap dealer for $2.00 a pound. The Coast Guard uses our range for their qualifications, along with a couple of police departments, so there's no shortage of .40 brass, believe me. I've tried selling it for the club to reloaders, but most of them want to pay less than scrap prices and balk at the shipping costs, which are flat rate boxes from the Post Office, with nothing extra charged for counting and packaging. At one time I had 5 five gallon buckets of once fired .40 brass in my garage, and after trying for months to sell it for basically scrap price, I finally took it to the recycler.
It's the same situation with 9x19 brass. We get lots and lots of it, and it ends up at the recycler for the same reasons. I use 9x19 for making .40 and .41 caliber bullets. I use .380 acp and .32 acp brass for making .357" bullets, and those are a little harder to come by, and I load for two .380 pistols, too, so I reload them a few times and then make them into bullets.
Hope this helps.
Fred