Look for cotton drill, sometimes called "pocket drill". If Wal-Mart doesn't have it, I know Jo Ann Fabrics carries it. It will measure about .015 in the store but once washed, it will have an uncompressed thickness of about .018 and a compressed thickness of about .008. This significant difference between uncompressed and compressed thickness will result in a good tight seal in your bore. 100% cotton drill is great stuff in most guns. If you want to give it a try, first buy a small amount to see if your gun likes it. Make a small identifiable mark on the end of the paper tube on which the fabric is rolled. I'm pretty sure you will find that this material will work for you. If it works for you like I think it will, go back and buy several yards from the exact same bolt. Look for your mark to be sure it is the exact same bolt of cloth. The stuff can vary slightly in thickness from one bolt to another so be sure that you get the same fabric that you tested. If you buy 5 yards or so, it will last you for a very long time before you have to go hunting for it again. But test a small quantity first before you buy a large amount. :thumbsup: