Barrel set screw was stripped (the head, not the thread), so impossible to tighten down. Managed to remove it. Will replace later.
Will order another barrel band just in case.
Turns out that not only was the barrel moving around , the muzzle brake was also moving around. Easily pulled it off and will test rifle without the brake. May eventually degrease it and epoxy it back in place. but for now why add vulnerability?
Ahh the joys of German springers suddenly become more evident.
Kris in NY