I don’t think the polymer (Tupperware) pistols will have much collector value.
Any of the quality steel and walnut firearms should increase in value, if they are still legal to own. Pistols like the S&W 41 or rifles like the Anschutz 1712 should maintain their value.
In 40 years what pistols do you think we will wish we had bought now?
All of them?
It depends on what you want them for. If you're thinking about resale value or collector value, you'll wish you had bought ones that are high quality, and maybe somewhat rare or special; guns that 20 year old people today are thinking "if I had the money, I'd get...". Because in 40 years, they'll have the money, and guess what old gun they're going to want? That top-of-the-line or special gun that they couldn't afford 40 years ago. See also: Colt Python.
But if you're thinking about enjoyment from shooting them or owning them over the next 40 years, it's much more subjective; buy what makes you happy.
i will add to my post here because i know i was a bit flip , i am that old and will not be here 40 years from now - im amazed im still here now , that said , i only invest in old items [granted much are from my childhood] that are well made and have stood the test f time [or mean something to me personally] we hold them for a while and enjoy them hopefully [its why i shoot mine] then another generation assumes control , LONG way of saying i only buy what inspires me - ill not buy a modern item thinking anyone will care after im dead , ill be dead , enough said ,
i do hope all of you that buy glocks and such enjoy them as much as i have what i bought in my short lifetime , im a steel guy mostly - i do have a couple but im not expecting them to accrue value to anyone but my heirs
I expect the value to be linked to politics and unfortunately, I expect gun control to be getting increasingly bad. If ownership is restricted, it also means that there will be a much smaller base of potential buyers. I do not expect it to be as bad as in the U.K. but looking at most European countries is scary. Until 1972 rifles were completely unrestricted in Germany and handguns relatively easy to buy legally, the market was flourishing then and most home owners had at least a .22 l.r. rifle in the house. Now these guns are sold off in a hurry as permits are revoked and harassing safe keeping rules are being thought up and heirs aren't allowed to inherit functional weapons.
In the 1960s a very prominent German politician had stated that a country is only as free as its gun laws, when they had just pretty much reinstated the RWG of 1938, the gun laws of the Third Reich!