I use these types of studies and news stories as a shopping list :)
Democrat supermajority in legislature and Obama elected (coupled with cheers from gun control groups): immediate purchase of AR lowers, A2 flash suppressors, folding stocks
Study/congressional murmurs about 5.7? Purchase! (with the extra evil 30rnd magazines of course)
Lots of negative TV press about 338LM (various "crime" tv shows where characters freak out over it's capability)? Savage 110BA Purchase!
ATF study on "non sporting shotguns? 870P purchase (Thursday, thanks for the excuse :) )
If only I was older in 1983, I would have stocked up on M16's...would have beaten the DJIA by a significant amount! (M16 in 1983, $2-2.5 or less, now $16k+, or a 6.5-8+% annualized return) (before anyone does the comparison, it beating DJIA is due to capital gains taxes on the stocks, and not on the guns for a private seller). Hell, 5.56 ammo has gone up 50% in less than 4 years (9-10% annual gains).
I laughed when one of my interns suggested firearms (as long as you keep them in good shape) and ammo (provided you don't shoot it all, I use a shoot 2, buy 4 strategy as a hedge to levelize my ammo costs) as "investments"...until I did the math. Then I started buying. While I don't see major regulations that would yield the effects of the 1984 law, there is truth in the fact it is virtually impossible to get minor regulations repealed, so with a steadily increasing population, and every year fewer suppliers, prices will trend upwards.
I also laughed at my cousin buying gold 4 years ago...wish I would have listened, he's made 150% return already. (that being said, don't buy gold now, unless you are betting on total collapse, above $1000/oz, even played out mines can be profitable, they just take a few years to start up, so I think it will settle back down, same with silver (though, silver has a little to go, but insufficient in my mind to make up for opportunity cost and buy/sell fees)