Yes, "New" and fairly easy to find for easy instant purchase is what I meant. The problem with rare used firearms is that are being sold already at a premium and you have to go treasure hunting for them. You also really better know what the heck you are looking at or you can lose money or get ouright ripped off!
It seems the general consensus amongst most folks on another websight is that I should be seeking class 3 weapons. (but I'm not interested) Just for conversation purposes, I can tell you that a fully auto Colt AR15 rifle that I could have bought in nice condition for $5,500 in 1995 was going for $13,000 a couple of years ago the last time I checked. (Don't know if a mint one would be $20,000 now!!) Of course, class 3 weapons are difficult to legally obtain, and I care NOT to register with the Feds and have to open and maintain a private corporation yearly. ( Without a corporation, the only other way is to find an official in your city who will sign an approval for you to buy a "machine gun"... yea right!)
A current example of the kind of oppportunity I'm talking about is the current LEO stamped Colt AR15 semi-auto rifles that you and I can buy, and are being phased out as we speak. You can buy them now for $1,050 before they are gone from inventory and replaced by the "sporter" models. I'm sure that in 2 years somebody will pay you $150-$200 more for that LEO inscription. (if it's kept new and unfired) If Romney or Obama seriously talk about a ban, that rifle will then sell for $2,000 But, without planning on a ban which would bring you a 40% overnight return, the LEO inscription on the rifle will get you a 10% return. (That's still 5 times better then the current rate of a CD!) However $150 ain't going to make me or you rich either. If you plan to be engaging in any kind of quantity purchases then you're "in the business of selling guns" without a license.
The only other weapon I am aware of in a very niche market are the 50 caliber $8,000 Barrett rifles legal to anybody who's eligable to buy a Remington BDL (and who doesn't live in CA or NY). But, I'm not sure what the rate of return is on those beasts. If you could make a $grand on one of those rifles after a 3 year wait, that would be a good return. (10%+)