It's very helpful, thanks! I read up on the Hornady thing. Seems you gotta be sure the threads are tight, you might want to use a dowel "stop" down the barrel, and more... would have been nice for Hornady to include those tidbits in the instructions. I too loose-necked a casing and tried your method. Better results, but I am still coming up with COALs that are below the 2.80" minimum length for the 175gr Sierras... I'm pretty new to reloading, and below min length makes me nervous. So, back to the drawing board. I'll buy a comparator and try measuring to the ogives with that, then work out a COAL, after my OCW tests are done and I whip up a batch of varied lengths to see if groups are tighter with that variable. Meanwhile, I'll load 'em to 2.80", like the GMMs...