Different alloy! Assuming you have access to high dollar metal forming equipment you can make your own cases. Also the slug usually goes through half a dozen or more intermediate stages. The crap’s not cheap but super cool.
OP4 mentioned in post #12 decapping Berdan primed cases. The easiest way I've found is to secure a straight sided punch that closely fits the case mouth, fill the case with water (oil will work but it's messy and harder to clean out of case), I had a block of steel with a hole half inch on one side and quarter inch on the other to hold the cases, insert the punch into case mouth and give it a sharp rap with a small hammer (preferably not steel). I have also seen articles about modifying Berdan primed cases to use battery cup primers. Kinda moot point right now.
I sized and primed a bunch of aluminum cases. The primers went in pretty loose on some of them. Probably use them as altor ammo. That way when primers falls out during extraction it's not going to cause any problems.
Yeah i’ve reloaded them once through but wouldn’t do more than that. You fail them and the burn through can damage you and your weapon.
