Investment advice:
You need to think through this a bit further. How many guns are you planning on buying in this "investment"? If only a small number, say 10, you won't see much profit even if the prices double in ten years compared to other possible ways you could invest the same amount of money. If you are planning on buying dozens or hundreds of guns, you will be assuming a massive risk given the costs incurred for each individual transfer, insurance, upkeep, storage, etc. The feds could fail to ban as you hope (yes, I said *HOPE*--which draws my ire, if not anyone else's around here), or the feds could ban completely (e.g. confiscate), or they could just ban the caliber of ammunition, or the guns could rust while in storage or get stolen from storage. There are many ways in which your "investment" could become worth less (or plain worthless) than you have invested and only one way that you can profit. With collectibles, loss is the most likely outcome.
You can never do well trying to time a market, especially if government regulations are involved. Enron was the last one to attempt this on a massive scale by posturing to trade in carbon credits that never materialized (well, that and horrendous accounting practices--but the bad accounting came after they were in trouble).
If you like guns, buy them, but don't think for a second that they are some sort of investment.