Code:
public fw_TakeDamage(victim, inflictor, attacker, Float:damage)
{
if ( is_valid_player( attacker ) && get_user_weapon(attacker) == CSW_AK47 && g_HasAk[attacker] )
{
SetHamParamFloat(4, damage * get_pcvar_float( cvar_dmgmultiplier ) )
}
}
In checkModel() you should use read_data(1) instead of get_user_weapon()