I recently tried 5/16" ramin wood shafts in my 43#@ 27" Hill longbow. With self-nocks and plenty of feather, they finish up about 475 grains and fly better than several different species of wood shafts I've tried in 11/32". I bought a dozen from Twig Archery and I have to say that, out of the box, they were the straightest wood shafts I've seen in a long, long time. If the spine weight is the same and the weight per inch is similar, why would these smaller diameter shafts prove consistantly more accurate in my non-centershot longbow than 11/32"?