Good guns will hold or rise in value over time. But many times it's a you have to watch things and time sales at just the right time. I use dot buy a lot of hunting shotguns when there was no hunting going no and was not going to be for a while. A little before turkey season I could unload them and make a few bucks. Older guns with historic value might be a better investment but that market is really customer driven so it's hard to tell when/if you can get a good return on them.
It's not the most stable way to invest and the gains are usually not all that great. But you can make some money if you shop right. I lean more to things liek gold and silver though. Silver is still cheap enough that you can get a decent amount and sit on it and it will make more than you have in it in fairly short order. I lurk eBay and the like for what is listed as junk silver coins and OZ bullion. The collector value isn't there but you are getting decent weight They also in case of bad times will still work as currency. Old nickels are kind of cool too. Pre 64 coins are made of nickel and are worth their weight even if they are trashed. Ones minted form 1942 to 1945 (Wartime Silver Alloy) have a little silver but I don't think it's more than like 15%. I can't remember to tell the truth the actual percentage.
AS got gold...The stuff is worth it's weight ion gold! Nuff said there.
The big plus to the coins over things like guns is you wont get your coins used against you in a worst case scenario.
A little food for thought...All the pins on the bottom of computer processors have gold pins. I like to try and reclaim them when I'm trashing an old machine.