I have been looking for a mod that reduces the amount of weapons available in the game, but all I can find are mods that increase all loot. I think it would be much more exciting finding a weapon if it only happened about 10% as often as it currently does. You'd need to swap that one pistol around your community to whoever is making the loot run that day instead of having an entire community outfitted like a first class army. I do play on Lethal usually and there are still too many weapons found in containers, in my opinion (just throwing that out there ahead of time since that was what was suggested to me on Discord).
If anyone knows of any mods that do this, or knows how to edit the loot tables and can teach me, I'd be very grateful!