as for issues with firearms .... some firearms (KelTec Sub 2000 carbine for example), particularly blowback design, do not always reliably handle aluminum cases. Similar to steel cases, aluminum doesn't properly retract it's size after firing, unlike brass cases, which makes for sticky or poor extraction/ejection. I doubt that's a concern of the "range". I figure the "range" does NOT want to sort out the aluminum .... and unlike steel cases, it can't be easily removed with a big magnet
JD