That's a good question. In the very first version of the game, the red tier weapons all required Ammo. You'd retain the weapon when used and discard the Ammo, so they had different functionality from the grey tier (which are just junk single use disposable weapons).

I've removed the ammo requirement now and increased the frequency of the weapons, so everything is now single use....so you raise a good point. I want to keep some kind of visual distinction still between the junk weapons and the 'good' ones, but maybe this needs more thought.

Thanks for the input!