@zepher nails it! If one buys fine firearms at a good price, those firearms will hold value over the short term and gain value over the long term. No, most won't increase in value as much as even a good index fund, but it is not like throwing money away.
I have been a firearms affectionado, i.e. gun nut since age 11. While my safes do not hold $50,000 rifles and shotguns, there are many very nice rifles and a few shotguns that won't embarrass my hunting dog!
I have long pondered that some collect things be they guns, watches, cars and so on. Others collect trophy heads to mount in their man caves. Then some collect adventures such as the next hunt in Uganda or other seldom seen places. I believe many of us fall within two or more of these categories.
As a gun collector, I have a few rifles that I will keep until I grow far too old to enjoy them. These or those that I've hunted will like my custom M98 in .22-250 that together we've slain hundreds of woodchucks some 40 years ago. Another is my Heym 88B in .458 Win. I've recorded over 750 shots which I've put down her tubes and taken buffalo, giraffe, zebra, lioness, and a tuskless with her.
Since I have no heirs that would appreciate my rifles a tenth as much as I do, most will be sold to new caretakers one or two at a time. Some of those sales will fund my last African hunt. My most cherished guns will part my caretaking about the time I need a walker to go from room to room.