What I hear you saying is that the reticle is moving, not being steady, as you shoot, right?
Being a 6mm Norma BR I'm guessing the rifle isn't a hunka junk off the cheaper than dirt rack.
If the rifle is steady, as in not moving around at all, and the target is dancing the jig, most likely, mirage is the problem. If using a variable power scope some think turning the power down helps. I'm not one of those! Mirage will tell you what the wind is doing.
Stack your rear bags such that the cross hairs are centered on the target with no human interaction. Don't touch the rifle with your cheek and look through the scope. The target should be steady with movement due only to mirage.
Watch the bull dance around. If holding steady on the bull's eye, you'll not be able to shoot a group smaller than what it is dancing.
If the target is steady and the rifle is moving around, this looks nearly like the above, then there are human factor/pilot problems.
Another suggestion is to snoop around for a mentor. There's gotta be some one in your neck of the woods that shoots benchrest or something that could help you.
I spent today with a young fella who hadn't shot over 300 yards. By the time he was done he was a regular hitter at 1000 and 1180. Do some snooping.....
Just a suggestion.....