Bounty Bob Strikes Back by Big Five Software.

This title is know in the C64 world as one of the hardest to copy disk out there.

The only thing thought I knew of that could copy it was Jim Drew’s SuperCard+ and a custom copier.(Version 3 of the Supercard-Plus.)

There are also different version of this disk.
It is also reported that Big Five software never used mass duplicators.

Jim Drew reports that this used completely aligned half-tracks.

C64preservation.com reports that most tracks are in custom GCR format offset 1/2 on each halftrack. Lower-grade version of Spiradisc-like protection from Apple II