Chopper spawns will yield you top tier weapons. I have 2 of every weapon in the game or more and all are off dead players or chopper spawns. No duped bases found and I play alot!

Just remove the glasses you are wearing and/or equip a tac light to the helmet. This will bring the toggle lights option back to the hotswap wheel

Almost all duping for xbox is removed. It is still happening but most if not all the guns listed above only appear on heli crashes as stated above. So duping of items is no longer the issue it was

This is a constant issue for me also. No fix yet