The most commonly used patching materials are striped bed ticking, Indian head muslin, sail cloth and denim. Why a patch? In a patched ball gun, an undersized ball is spun by rifling, and the ball never touches. Gripping the patch tightly, the patch takes the rifling and implants spin to the ball. As the spinning ball leaves the muzzle, the patch falls free. Why is the patch used? Because it would be difficult to ram a ball down several feet of bore as the lead takes the rifling, even with a clean bore. Another major purpose of the patch is to act as a gas seal. Thus, the thickness of the patch and its relationship to the depth of the rifling and size or the ball, along with powder charge, determine the accuracy of the gun. Each gun is a rule unto itself and you must find the proper combination by shooting. Patch size will generally be between .005 and .020 and will most commonly be between .010 and .020. Retrieve those patches and look at them. The drawings below should help.
(A) Indicates that the patching material was probably too thin for the ball diameter and was badly charred by gas leakage past the ball. Sometimes the patch will be completely shredded.
(B) Sharp wire edges on lands made these radial cuts. Scrub bore with steel wool to remove them.
(C) A circular cut would be caused by too sharp an edge at the muzzle. Chamfer it slightly.
(D) If a pre-cut patch was used, this would show that it was not properly centered, causing inaccuracy.
(E) The way a fired patch should look – centered, no cuts, no charring, no blow-by.