I appreciate I only have a low post count here but I have been shooting for some years so here's my tuppence worth....
Mounts need to be tight, particularly on a spring gun. Arrestor pin fitted. Everything else tight.
Could possibly be a dodgy scope, could you try another one?
Cant and scope alignment will have no effect on grouping at any given distance.
There are loads of variables, is it pellet fussy, is it clipping( if a mod is fitted), has the crown been damaged?
Do you have experience with a springer? If not, give it to someone who has to try. If they can group well