There's a lot of panicked buying going on in general
It's become a joke how much people are hoarding toilet paper (in the US, in particular, it wasn't hard to find before this). But hoarding things is part of a broader issue (emphasis mine)
Australia has also suffered from panic buying of toilet paper despite plentiful domestic supply. A risk expert in the country explained it this way: "Stocking up on toilet paper is … a relatively cheap action, and people like to think that they are 'doing something' when they feel at risk."
This is an example of "zero risk bias," in which people prefer to try to eliminate one type of possibly superficial risk entirely rather than do something that would reduce their total risk by a greater amount.
Hoarding also makes people feel secure. This is especially relevant when the world is faced with a novel disease over which all of us have little or no control. However, we can control things like having enough toilet paper in case we are quarantined.
Guns still mean security to a lot of people
Guns are still a powerful way to protect oneself, and more than a few people fear social breakdown, despite the fact that no place in the US has suspended their police force due to the pandemic, nor are there widespread shortages of police. As such, people want weapons to stop intruders
Hyatt said that the type of guns being bought was reflective of the fear prevalent among customers. There was almost no interest in hunting rifles. Instead, people were opting for target guns and there was big demand for AR-15 semi-automatic assault-style rifles.
Asked why he thought the spike was happening, Hyatt replied: "Financial meltdown, pandemic, crime, politics … you throw it all into the pot, and you have one hell of a mess."