Tom Bowers at subguns.com....
http://www.subguns.org/products/mags/
M3 "Greasegun" .45 Caliber Steel Magazines:
These are new in waterproof wrap.
Pricing: $16 each, price includes shipping and insurance.
Large quantities up to ~2000 units available, call for quote.
Federally unrestricted. You are responsible for compliance with your state laws.