i think the tried and tested method is the boss metal zone...
personally i tihnk a decent combo amp set on the overdrive channel... and use a ts-9 to boost it over the top will give a much better dist. also add a compressor to keep that tight chug ....
i heard a tech21 trade mark 60 - ts9 - boss compression sustainer .
heavy shit... really nice chug tone... metalica rythm tone is damn solid...
well the old metalica that is... james hetfiled... respect.
