Screw it, when I get out of law school I'm going to invest heavily in class 3 NFA weapons. Yes I know that even a slight change in federal laws will make them much less valuable, one way or another, but I don't see that happening anytime soon.
If I was going to invest in anything right now I'd start buying up Vector Arms UZIs. What's the difference between an $8,000 Mp5 and a $3000 Vector? The difference is, there are ALOT more Vectors on the market---when the supply from Vector runs out in another couple of years, the price will jump right up to where all the other submachine guns and registered receiver guns are.
Hell, at least its alot more interesting and enjoyable than buying stock in some company I've never heard about and then biting my nails while I watch the ticker tape go by under the 24-hour news channels.