[Grim_]

Increasing their skill level by 10 each time won't show immediate affect each time, so it will take time to get a higher level. Example of how this could be worked is shown below:

pawn Код:

public OnPlayerDeath( playerid, killerid, reason )
{
   if( reason == 31 ) // M4 weapon ID
   {
      SetPlayerSkillLevel( killerid, WEAPONSKILL_M4, M4_SKILL[ killerid ] + 10 );
      M4_SKILL[ killerid ] += 10;
      SendClientMessage( killerid, 0x00FF00FF, "Upgraded your M4 skill. Keep practicing!" );
   }
   return 1;
}

Of course, you will need to create the M4_SKILL variable for each player, like so:

pawn Код:

new M4_SKILL[ MAX_PLAYERS ];

Remember to also reset the skill level to 0 after the player connects to the server,

pawn Код:

public OnPlayerConnect( playerid )
{
   M4_SKILL[ playerid ] = 0;
   return 1;
}