260 rem groups puzzling me!

[8 ball]

Nope! Only reporting what we've had happen! Your right, it doesn't make a lot of sense.

 

[Obtunded]

This will answer the question a little better.

http://www.appliedballisticsllc.com/index_files/EpicyclicSwerve.htm

 

[JEC]

Interesting theoretical on the epicyclical swerve. If I'm understanding it correctly, there is potential for the bullet to swerve back towards the centerline to the tune of somewhere between .02 - .05 MOA. That would seem to be inperceptable on paper?

 

[J.S.G]

Sorry, have been away from the action.Thanks Obtunded for the read and the rest for responding.