Re-run of something I posted in the past:
I had to make up a decorative brass tompion (muzzle plug), like the ones we used aboard ship in the Navy for the big guns, for a 3 inch bore cannon last week. It got me thinking.
Not long ago Ron Scott was kind enough to send me several small scrap pieces of exotic woods to make up some of the whisk and vent pick sets I have made. I had one piece of burl locust that was long enough to make the handle for a vent pick and there was enough material left to do something else with. So I made this tompion (sometimes spelled as "tompkin") for a .50 cal English rifle I am working on. This is a simple one with a split wood shank. I am making several others out of horn, bone, antler, etc., with more elaborate muzzle retention features like an expandable leather washer. Fun to make and keeps the rain, snow, dirt out of the bore.
Here is the original thread - a few pros and cons about tompions, but I have never had any trouble and I have fired several of them away on purpose just to see what happened...no problems.
http://americanlongrifles.org/forum/index.php?topic=10749.0