doc, just try the 42.5 grains with a seating depth change, .005" shorter, and again at .005" longer. If it's on a true accuracy node, it'll tighten up and get rid of the linear group. That said, 42.7 may be closer to the actual OCW high node. And 41.4 to 41.5 on the low node is probably where you'll end up at.