The counter should count ALL kills with ALL copies of the gun, not just that specific copy of the gun, not just from when you have that counter type active no no no. Masterworking the gun should merely buy you the right to display the counter, nothing else!!! It should be counting from the second you start using it. And this also comes into my other posts about all exotics getting a catalyst/Masterwork. It's kinda ridiculous TBH, older exotics only having a PvE counter and no PvP one, half the exotics In the game unable to get one. Seriously Bungie!!! The Killcounter System NEEDS some love!!!!!!