Mr Pogo -
Welcome Aboard !My concern for aluminum cases comes from an entirely different quarter. If you're truly concerned about the price of volume shooting, then you might be "pinching pennies and loosing dollars". Just wondering if you happened to read this thread:
https://czfirearms.us/index.php?topic=58939.0 ?
So my concern stems from the fact that aluminum cases can't be reloaded, whereas if you paid a penny more per round, then you'd end up with reloadable brass cartridge cases. Any cartridge case represents about 2/3 of the price of the ammo, no matter what material is used. So when you shoot your 100 round box at $33 and walk away,
try to think of it as leaving $22 on the ground. If you want to throw down and walk away from $20 bills, then please, by all means, come shoot at my house !!
Generally speaking, 9mm brass can be loaded up to ~25 times. So when you buy brass-cased ammo that $22 goes back home with you and is conserved. Eventually it's reused as THE major component in the next batch of reloads. This all starts with buying a cartridge case material that's worth picking up and recycling.
Right now I'm paying about $9.50 for the same 100 rounds you want to spend $33 on. Except my ammo is made with the
finest materials and is tuned to my gun to deliver
maximum accuracy. So for price and accuracy it's worth considering.
Hope this helps.