I don't see why they wouldn't be. They're not serialized and don't require a manufacturer marking.
As long as they're compliant with any pertinent laws, I don't see how they could be illegal to make. It's legal to make a firearm as long as you don't intend to sell it.
I don't know of anyone making mags, but I was actually thinking about it last week! I was thinkin that it would be a huge PITA and it would be very ugly...
"If you're not shootin', you should be loadin'. If you're not loadin', you should be movin', if you're not movin', someone's gonna cut your head off and put it on a stick." -Clint Smith
Last edited by samuse; 01-19-2013 at 20:52..