I went to a craft store and bought some .005 copper sheets (on a roll.) I also set up the punch with an arbor press so I get consistent pressure and depth to the punch. Now i get usable caps. My only problem to date is drying out and losing the priming mixture from the caps if they are not carefully handled. I keep them in a primer tray with individual holes, which helps, but if they are jarred, they lose content. Clearly this is a tool for emergency use, not to make a large supply of caps for regular use (imho).
ADK Bigfoot