Dave is right, of course. A 1/4" rod will fit the thimbles on my .25, but will not fit the hole Mark Wheland drilled in the stock for the hickory rod he fashioned. Some 1/4" rod will not fit the bore of the barrel without lapping the rod a good deal. Some will fit--tightly--out of the box, but leaves almost no room for air. Don't expect 1/4" rod to mic at .250. I'm confident Ed Rayle bored my barrel almost dead nuts .250, not leaving wiggle room for .250 rod, brass or steel. I use 7/32", and can't recall my online source.
