if you can't fix netcode how about making a script like (ruger-hit-head-ruger-hit-body then -Die)
I know this is not how the netcode looks like but i'm just giving a basic example
Thats the thing - the game sometimes doesn't realize if there was a hit. The game doesn't just go "hey, he shot that guy in the head with ruger, but I'm just going to let him live for no apparent reason".
The way it works is something like this:
Player: "hey, I shot that guy in the head with ruger, he's supposed to die!"
Game: "oops, my bad, that shot actually missed but I didn't have time to show that on your screen because there's so much data i have to send and receive that i get confused sometimes".
Sorry to break this to you, but netcode really isn't that easy to fix, otherwise it would've been done already.