[Flake.]

Seriously? Do you even bother to search.. There are loads of scripts for this.

Never the less..

pawn Код:

new Float:HP;
    GetPlayerHealth(playerid, HP); //getting the players hp blah blah
    if(weaponid == 23) SetPlayerHealth(playerid, HP-25); //If the player shoots someone with weapon id 23 it will take -25 damage of their current hp
    if(weaponid == 25) SetPlayerHealth(playerid, HP-46); //same with this

Use something like that for OnPlayerTakeDamage