280 AI weird groups??

[Montana'eer]

I have a fairly new .280AI. 700 trued action mated to a Brux barrel, heavy contour and in a McMillan Rem hunter stock. I had the same problem. I had found a couple powders that worked using Peterson brass and Federal TA 155 bullets. However same as you- 2 touching one flyer. At about the sane round count as you- I cleaned the barrel down to zero (completely) and took it to my gunsmith. He scoped it and about 3/4 towards the muzzle end there was a mar down the rifling about 3"-4" in length. We sent it back to Brux and apparently they failed to do the final lapping. Got it back and it's better- but not bug hole better. Sub moa at 100yds.

Check your barrel would be my advice.

 

[Jeremy Henderson]

I had the same problem with my 6BR. What I found was measuring each case I had a few that were.002 longer trimmed to the others and the flyer stopped. Hope you get it figured out.