Last September as Hail To The King rose to top the album charts, Machine Head mainman Flynn scoffed at the band's achievements and suggested they were ripping off other acts.

But now Flynn tells Metal Hammer: "Oh man, I just feel that bands should be accountable to each other and if someone's not pulling their weight, say it. What's wrong with that? It's not out of hatred. It's out of love. Try harder, motherf***er"

Flynn's lengthy rant on Machine Head's Facebook page described A7X's album as "a covers album" adding "who knew that re-recording Metallica, Guns N' Roses and Megadeth songs could be such a worldwide hit?"