Thin paper v thick paper?

[MikeR]

mhearth; You are correct in thinking, measuring paper is more of an art than science. And there I no magic fit. There is a whole range of sizes that will work correctly. For target work the patch must hold the bullet centered in the bore. This can be as loose and able to free fall through the bore to requiring considerable pressure from the thumb to seat the bullet and cartridge. As long as every bullets is the same there should not be a problem. If you have bullets mixed where some are tighter than other you are asking for more vertical.

MIEagle; Wrapping twice around a bullet or mandrel is the best way to get an idea what your paper thickness is. Normally I don't concern myself with the groove diameter. When the powder goes off, the bullet will fit the grooves perfectly. But in your case, if the bore diameter is truly .403 and the groove diameter is .408, then I would go with the thinner paper. My concern is, a .396" bullet with even the 9# paper will not fit the bore closely. A .396 bucket wrapped with .006" of paper will be .001" below bore diameter.