Cal45, the product was Forster's Tap-o-cap. The device looks like a two piece punch, and it punches the cap body out of an aluminum soft drink can you've cut open. Then, you take a single powder 'dimple' (or maybe more than one) from a roll of kid's roll caps and put that inside the cap body. Midway and Possible Shop both list the Tap-o-cap. I guess kids' paper roll caps are still available nowadays.
If you do a Google Search on "Tap-o-cap" you'll get a fair number of hits, including discussions in other forums on the merits of the device. From what I read, you got better results using the caps on a revolver or in-line because you had a straight path to the powder, and there was a lot of variation in quality of paper cap.