The only thing I see affecting gun prices is the election.
As for guns as investments, investment guns are investment guns. Plastic guns are tools. The former is generally a good investment and will always appreciate, either slowly or quickly depending on a number of factors. Machine guns are a good holding investment. But mass-market utilitarian guns, produced in the millions, are a tool meant for self-defense and should be purchased based on how well they serve you in that regard, IMO.
With the exception of certain extremely rare pieces if bought low (estate sales) and sold high, you're never going to make the kind of money you can make in the stock market. You have to know what you're buying to do that, as well. Someone might think "aha, a Webley MK VI, that's valuable!"...and buy it. They might not know that it's a mismatched and cold-blued parts gun with a shaved cylinder instead of the original .455 caliber, making it worth less than they paid for it. I've also seen at shows "Genuine Colt Government" 1911s. Slide from one, sure, refinished. On a newly made frame from the Philippines. It's a very tricky market that requires a lot of research, or you just get burned.
Besides, if you buy and sell too often to individuals, you become "in the business" to BATFE. If you're selling to dealers, you are not going to get a good price, as they want to make a profit, too. If you want to do that, get an FFL.
