Hamster wrote:MAG.
Dboys.
All I can think of.
And ask google for more information regarding your product.
How informative....
Magpul is out, because they weren't around then, and if you're going for the legit Vietnam era look, he should search for stamped metal magazines. I did some searching and here's what I came up with:
Mids:
http://www.airsoftoutletnw.com/index.php?page=shop.product_details&flypage=flypage-ask.tpl&product_id=1578&category_id=179&option=com_virtuemart&Itemid=28
Inexpensive Hicaps:
http://www.airsoftgi.com/product_info.php?products_id=2383
I understand your friend doesn't care if they're mids, standards, or hicaps, but standards are hard to play with if you don't know what you're doing, and if you're about to spend $50+ on magazines I would suggest figuring out what you're looking for. Hicaps are great for starters since you don't really need a vest, you can just pack a magazine in each pocket, and one in the gun and you're basically good to go, but if you already have a vest mids are nice, since you don't have to wind them, and they don't rattle like a cement mixer full of marbles.
EDIT: relevance.
Basically all M4 magazines work in all M4/M16 style rifles, if you're concerned about it I would call somewhere like Airsoft Outlet NW, or AirsoftGI and ask a customer service rep about it.
"No compromise, not even in the face of Armageddon, it's always been the difference between us, Daniel."