Hetfield made the revelation during an appearance on EMGtv where he was discussing his new Het Set guitar pickups. He said, "We're recording right now, and there's the number one guitar, the number two guitar and here's the third-track guitars that just sound different. They all sound different."

hennemusic reports that the band spent much of the spring and summer on the road while they worked on sifting through hundreds of riffs for the project. "We have a lot of good songs," revealed guitarist Kirk Hammett in April. "The songs are ever-changing at this point. Nothing is etched in stone. We still have a lot of material have to sift through, still. We have well over a dozen songs and we still have well over two or three hundred riffs, too, so it's hard to say at what point we actually are in in the project.