I've never made any caps with one of the cap makers; however, I had some kids roll caps and since I'm in the leather business, I wanted to see what size leather punch would punch a perfect diameter slug with the primer dot on it to fit into a commercial percussion cap. I found that a hollow tube leather punch size #4 or #5 (11/64" - .171 dia.) works best. The actual diameter of the punch tubes will vary according to the tool manufacturer. Using a hollow tube leather punch is more accurate and faster than trying to cut these out with scissors or separating the two layers of paper in order to recover the priming compound. You do have to be careful not to cut into the edge of cap primer, if you do it will probably set it off. I also wouldn't let numerous caps stack up in the punch tube, if you do detonate one, all in the tube will go off. I removed the slugs (dots) from the punch tube with the flat butt end of a bamboo skewer. Weaver Leather has a rotary leather punch imported from Germany, which is good quality for the cost, under $20 at Amazon, and free shipping if you have Prime.
Weaver Rotary Leather Punch
I've seen some of the caps turned out with the Tap-O-Cap and read where they work, but that is one ugly cap. Kind of like a cheap ugly straw hat compared to a Stetson. The finished cap reminds me of those accordion cupcake papers you use in the cupcake pan, just not as clean looking. Here are the dots, the punch is a single tube C.S. Osborne Mfg.
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