There will always be Kalashnikov rifles, millions upon millions are stashed in cashes all over the world, if 99% of the human race died out, there'd still be enough AK model rifles to arm the entire 1% left over and ammunition to boot.
Ukraine has 7 million AK model rifles and 11 million tonnes of ammunition stashed, and that's just one country, and one series of rifles. Guns aren't going anywhere.
So absolutely no reason to horde sticks and stones. Don't invest in gold, buy salted ammunition. In the event of a mass extinction you'll be melting down your gold to make bullets inside of a week.