I have a video Titled IN THE STYLE OF METALLICA. In the video it talks about gear setup and how to get that crunch. altho they prefer you to use marshell amps it can be uptained on other amps if you have an EQ or tone nobes on your amp all that it says to do is cut out the mids and crank all the lows and highs. then kick up the gain all the way and add some distortion and you have as close as I have gottin to Metallica's crunch with out having the same exact setup. hope this helps those how are interested in the sounds of Metallica.