SharpDog, you need to be careful with the ammo and weapons because they may use them on you if they know what you have.
Everybody needs to be very careful when trading any item, not only weapon. Being something like “famous trader” or “man who have everything for trade” may be good in some organized SHTF community, in small town for example.
But in real urban SHTF scenario, you need to be trader without letting folks know that you have stuff for trade. It sounds weird, but you need to more or less hide that info, using the for example middle man for trade (or more of them), not using your home for trade, hiding it actually, trading things only in small amounts etc.
It all goes in “low profile” policy.