[Pawn] Help with Damage System

[Snow]

You can use the weapon-config
https://github.com/oscar-broman/samp-weapon-config

The op clearly mentioned he does not want to use any includes/fs.
You can modify the damage under OnPlayerTakeDamage & OnPlayerGiveDamage. Like this

Code:

if(weaponid == 26)
{
    SetPlayerHealth(playerid/issuerid, -60.0);    
}

This will remove 60% of the player's health. Use issuer/player id accordingly to the callback.
But I'd still recommend you to use the weapon-config as that's pretty much better than configuring each and everything on your own.