That was awesome Jester. Thank you.
To recap:
Casing
Brass casing is best on small arms rounds because you can reload - steel is a one shot deal. Everything over 20mm/mortar rounds will use a steel case anyway and cant be reloaded.
Projectile
Lead is suggested but jacketed steel or ceramics can be used for small arms. 20mm+ will all be steel usually.
New question: What about shotgun shells?
Production numbers are really off for me though. I understand actual experience might be easier but I need to some how develop numbers based around either the core rules or some sort of mathematical formula or soemthing.