need script:Headshot=2Frags

[Feralidragon]

why is the killer.killcount += 1; needed?

need script:Headshot=2Frags

Headshotgives one frag.1 frag is manually added to make it count 2 frags for each headshot

killer.playerrplicationinfo.score += 1
already does that

Right and wrong actually.

Score is the overall points a player has in a match, Killcount is the amount of frags only. In DM these 2 values are always the same (you get 1 point for 1 frag), but in case of a CTF for instance, this is not the case: you will have a certain score (playerrplicationinfo.score, based not only in frags, but flag scores and such) but a different number of actual frags (killcount).

So if you want to increment the frags, you have to increment BOTH the score and the killcount. In case you increment the score only, certain statistical mutators will give the wrong value relative actual frags, since they see the Killcount.