A major part of Hetfield's sound is in his right hand technique. Once you get that part down then it is a matter of playing through a relatively high gain amp that is still relatively clean. You need to maintain articulation of the individual notes. Realistically you don't need James' gear to sound like him. He sounds like him no matter what he plays through. I would say practice playing his style. He typically plays all downstrokes with the occasional upstroke out of convenience but he definitely isn't an alternate picking kind of guy. His right hand technique also includes the way he mutes. Once you get his playing style dialed in then move on to find the gear. This will keep you from being swayed before you know what it will actually sound like while you are playing. Yes, it is important to play on the gear that is used by the artist to really get there but you don't necessarily need that gear. Case in point, Metallica used a modded Marshall to record a mass of their material. They do not take it out on the road. Kirk used an old Gibson Flying V to lay down a ton of their songs. He doesn't use it live. Get the idea? Though they used dozens of amps to record the black album they didn't have them all on the road to support them. I think that if you get your playing style together and then get an amp that can get clsoe then you are basically doing what they are still doing. This having been said, a Triaxis with a tube power amp, a Quad with a tube power amp, a Mark IV, or even a Dual Rec should get you there as far as Mesa gear is concerned. Just do not forget that you will want a JC-120 for your cleans.
