Du Cann and Hammond had left Atomic Rooster due to disagreements with Vincent Crane over the increasingly bluesy, soulful direction in which he wanted to take that band.
Consequently, compared with Atomic Rooster's more progressive leanings, Hard Stuff were based more heavily on aggressive guitar.
[citation needed] Originally, Du Cann, Hammond and Shaw had formed a band provisionally entitled Daemon, with the intention of eventually touring and recording under the name Atomic Rooster.
Gustafson was invited to join them on that basis, but after finding out that Crane retained the rights to the Atomic Rooster name, the quartet decided to continue anyway, but under the name Bullet instead.
Prior to the release of their debut album, they were prompted to change their name yet again, this time to Hard Stuff, due to a legal threat from a US band also called Bullet.