Skizzums, if I had 20,000 pieces of mixed brass it would look, seem and -BE- a nightmare to consider sorting it, I would easily agree. But that isn't my situation at all. I have been bringing brass home with each range trip -- usually all or mosy of my brass and on some days, brass that was left there by other shooters and I have been doing that for 25+ years.
So I come home with a few hundred pieces of 9/.40/.45 at the most. And my .38 is in a bag, .327 Fed in a different bag, .357 in a bag, .44 Mag in a bag...
As to what I do differently by head stamp?
Already explained: I do nothing different, but each box of my ammo has the same stamp. All the ammo in the same box is as similar as I can make it, which makes for consistency, as much as I can make it. Consistency is what I am after, and for -ME- it provides a mental "chip" that my ammo is going to be the same shot-to-shot as it can be, so I can trust the ammo to do it's part while I focus on my shooting and not on my ammo.
I am not telling others they must do it. But this is my proces, it is IRRATIONALLY well tested and I am quite certain that the way I do it works extremely well for me.
Do I trim handgun brass? No way.
Do I clean primer pockets? Never!
Wet or sonic tumble with steel pins? Nope.
Buy new brass?! Never gonna be my first choice.
We all have our way. I know by demonstrated fact that my way works. I didn't just come up with my methods last week, I've got a lot of bench and trigger time backing up my process.