You should overclock each thing one at a time if you don't already know. Set everything back to default and work the gpu to the highest stable setting, then shaders, then memory. Make sure you setup a fan profile, those cards run hot and will be hotter when overclocked.
Also just because someone else got a particular overclock, doesn't we all can get the same, every video card is a little different.
Ok, I should start from zero, MSI has a lock for Core and shaders, according to your recomendation, how could I be able to OC them independently??