You can make your own bore buttons for a .50 caliber with a 1/2 or 9/16th hollow hole punch. Then get some construction wool felt at the lumber yard. This is the stuff they put around your doors and windows for insulation. I like to get the wide stuff.

If you want to purchase excellent quality bore buttons at a reasonable price, call 1-317-933-3441 the company is called Flintlocks Inc. John & Anne Eder make bore buttons and sell them lubed or unlubed. I get the unlubed. They are much cheaper them most of the other online stores. For information and prices, email them at [email protected] (information taken off their business card).