Muzzle Loader Originals Black Powder Shooting Patches are 100% cotton patches with pre-lubricated options or easier loading and easier cleanup. Thickness varies from 0.005" to 0.020" and are designed for use with a round ball. Patches are tightly woven cotton and are resistant to burning. Features100% CottonPre-Lubricated optionsVarious thicknesses to meet your specific loading needs Shooting Patches are designed to fill the space between round ball and barrel to provide proper seal and travel down the barrel rifling. The following general formula provides a starting point for determining the desired thickness of shooting patch: Barrel Diameter - Bullet Diameter = Patch Thickness For example, for a .50 caliber (.50") barrel with a .490" round ball, a .010" patch would be indicated. Please check with your firearm's manufacturer for recommended lead ball and patch sizes, and experiment within that recommended range to find the best performance for your gun.