As another point of reference, I bought many "high capacity magazines" in 2010 for range practice. In 2012 I sold all of them for 4x what I bought them for on gunbroker because of the gun ban scare.

The economics behind gun parts is wacky, and home production would be a radical shift in technology to finally send the cost downward.

Of course gun manufacturers would lobby against any home printing. How could they sell $2400 rifles when a decent rifle would only cost a tenth of that to build at home?