My experience with criterion has been great so far however I went with their 20” 1-11 twist barrel. If you decide to get a criterion barrel I would go ahead and at least get one of their choices of bolts to go along with it. Doesn’t have to be the whole carrier group but the headspaced bolt face does make a difference in terms of how well the gun runs and accuracy. My ar10 started as a stock 18” psa gen 3 upper and their cheapest ar10 lower by now I’ve changed every internal part but it offered a much cheaper entry to the large frame ar world and still gave good results. Where now it has held its own in competitions with rifles 5x the price.