The cleaner bullets were entirely designed and manufactured specifically to clean the bore on muzzle-loading rifles (rather than simply an insert for a standard bullet). The main nose section of a Williams Patent Cleaner bullet, is molded of lead with a hollow shaft hole at the base. There is then a bottom base of lead also or pin with a shaft (depending on the variety of Williams Cleaner bullet), that is designed to fit in the base of that specially designed bullet body. The zinc portion, is a thin washer, that is slightly convex, fitting in the gap between the bullet nose and inserted base. Upon firing, the base and shaft portion of the bullet is pushed up against the main nose portion, whereby the zinc washer is expanded outward, to assist in cleaning the bore of the rifle. Since the zinc washer portion is very thin, and considering that zinc does not withstand the elements of exposure in most ground conditions, accounts for few Williams Cleaner bullets being found with intact zinc washer portions.
The possible field-made "button" shown above, which is likely the base of a type II Williams Cleaner bullet, is in fact lead alloy and not zinc. The zinc portion would have been a very thin washer type piece, fitting on the shaft (now bent over). The zinc washer would have been larger diameter than the lead base of the bullet, yet the convex shape of the washer when manufactured, would keep the actual diameter flush with the bullet, until firing compressed and expanded the zinc washer. The length of the bent over shaft on the excavated example, of possible use as a "button", seems longer than what I've seen on the more commonly encountered Type III Williams Cleaner bullets. My hunch leans towards the Type II base as origin. The Type III was basically the same design, with a shorter nose and body section having two rings, opposed to the longer three ring version seem in Type II bullets.
Since Williams Cleaner bullets were prone to mishaps such as jamming when fired, experienced soldiers were soon removing the cleaner bullets from the cartridge packages prior to and during battle (originally 1 cleaner bullet was included with 9 standard rounds in a package, later increased during the war to include additional cleaner rounds). At one battlefield site in Tennessee that my father, myself, and associates were searching for relics 30 years ago, the vast number of dropped (discarded) Williams Cleaner Type III that were recovered, soon had the hill dubbed "Williams Cleaner Hill" by our group of relic hunters. Evidently this was a staging point for the battle, and discarded Williams cleaner rounds attested to the dislike by the troops.
Williams Cleaner Type I
Williams Cleaner Type III
CC Hunter
Got2dig sent me a Private Message, requesting me to view this discussion-thread and comment about his find.
Let me clarify about a statement made in a post in this discussion. On Williams "bore-cleaner" bullets, the only part which was made of zinc was the very thin, saucer-shaped washer. The base which held the zinc washer in place was made of an alloy of lead with a small percentage of another metal named Antimony. That alloy was called "hardened-lead."
The reason I put quotation-marks around the term "bore-cleaner" is that it is ONLY a nickname, apparently given by 20th-Century diggers and bullet-collectors, such as the authors of the McKee-&-Mason bullet-book. It is not called a bore-cleaner bullet in any civil war Ordnance/Bullet documents. The text written by Mr. Williams in his US Patent says the washer's purpose is to enable the bullet to engage the gunbarrel's rifling-grooves. The bore-cleaning effect was just a "side effect" of the washer's intended purpose. This information comes from "A Handbook of Civil War Bullets & Cartridges" by the Thomas brothers.
About Got2dig's find:
Its disc does seem the be almost exactly the same diameter and thickness of a Williams "bore-cleaner" bullet's base plug. (Some diggers call it the Williams "thumbtack", and the T&T book calls it a piston.) I think Got2dig's theory about his find being a soldier-made transformation of a Williams base-plug into a button is a reasonable theory. But Crusader's observation has significant weight ...it wouldn't function as effectively as desired, due to the thread-hole being very close to the disc's edge ...and that may be why it was eventually discarded or lost.
Thanks CC, I'am glad there is some one on here to help. But in the links that you posted it dose say the #3 has a flat zinc insert base. But the more I think and read the base was lead. Thanks for your help.