I found annealing to be critical for my 6.8 brass, otherwise neck tension was all over the place, but it’s a mixed bag of every type of factory 6.8 brass out there, with several reloads.
I tend to only reload the higher end Federal brass and the brass from Lapua or Norma factory loads from my bolt guns in my AR10 in .308, and typically only run reloaded Lapua or Norma brass through my bolt guns, but honestly, usually just run factory loads through my bolt guns and recycle the brass to my AR10. I typically anneal every other loading on those and have never had an issue; most only have 3-4 reloads on ‘em though.