This is just a guess because you give few details but as it is I am thinking a loose base or loose mounts. Or a bad scope.Shoot 10 rounds a minute apart. That will tell the story. If you get 2 groups either the scope is bad or something is loose. Also take the action out of the stock. If you see a shiny spot the barrel is bearing on the stock.I get these groups with a bit of regularity. The pairs won't necessarily always be in that same spacial orientation. Can anyone tell me what is most likely to be causing it?
I don't know anyone that shoots, so I think I'd either be looking at doing a warranty claim on mine with vortex, or selling it and getting a different brand.I'd beg, borrow or steal a different scope to try. If the talleys are tight, they should be fine.
Definitely some improvement but I think the load is still out of tune a bit. Next trip, I'd load 5 rounds exactly the same for comparison, 5 rounds .005 longer and 5 rounds .010 longer with out changing anything else.
Clean the barrel with solvent and a brush to get at least most of the copper out before your next trip. Hoppe's will take the copper out but it takes some soak time. If you have a more aggressive copper solvent, that would speed things up a bit. Then once you have the copper out, put a thin coat of thin oil in the bore. Load a couple of extra rounds to fire first as foulers, then shoot your groups.