To spice up the reason for PvP, it would be nice to introduce the "Legendary Gun Status". The way I see it, it is a gun that can be tricked out with scopes and whatsnot, and as such cannot be bought at a trader. Once the fee for Legendary Status is paid, the gun as such disappears from the game and becomes the sole property of it's owner. Only the owner can sell the gun back at a trader, and with that happening, that same gun can be found in the game and bought from a trader again. But without the Legendary Status of course. In the event that it's owner dies and respawns, the gun will stay at the spot it fell and cannot be recovered by someone else, but it's owner. Everybody can have one Legendary Gun, be it a rifle or pistol or revolver.
This idea can be plussed with all sorts of bonuses, like cheaper ammo and higher death toll due to the gun and owner became more of a "team". There can be detrimental effects too, like the ability to carry less loot due to the need to care for this awesome gun. Or when the owner is no longer in game, the gun has to be stored in a "gun locker" (a crate, safe or something) what the only place is where it can be looted, and sold for mucho poptappos. Or when a (high) fee is payed, it becomes your "Legendary Weapon"!
