Tks for the info. We don't have Joanne's Fabrics here, but still good to know.
The 12 ounce denim I can get here measures the same for me, at .025" compressed as hard as I can in my Hornady calipers. In my "other" calipers, the 12 ounce measured .030", but in my current Hornady calipers, it measures a solid .025". These measurements are what I also get with my mic, run on the ratchet only.
Without springing (permanently) the yoke of my micrometer, just cranking with forefinger and thumb, the barrel of the mic. I was able to compress the 14 ounce denim to .002",(yes 2 thou) repeatedly, so method is very important. That's the same material that measures .030" using the ratchet, same as in my Hornady calipers when compressed between forefinger and thumb.
Different makes of calipers will measure the same material at a different thickness. This is due to the width of the jaws, I assume. Pushing hard on the rotating little barrel of the calipers will get a thinner measure than pinching, but the pinching method is repeatable, over and over. THAT is important, I think & is the method I prefer.
Currently the 10 ounce denim we can get, is .021" and shoots well in every one of my rifles with balls running .010 (.350") to .005" (.495") under bore size. The .69 is used with the same patch, with a .682" ball.
I use the 14 ounce denim with the .677" and the .662" with virtually the same accuracy as the larger ball & thinner patch.
That natural duck at .022" sounds super for most guns, HighUintas.