Howdy
I had one too. It was a rip off, back before the word was invented. It was about as close to false advertising as you could get.
The gun was made of plastic. Just two halves glued together forming the entire gun. Oh, it looked great from ten feet away, but it was made of black, injection molded plastic. Inside the molding the barrel was a cheap piece of tubing, extending the entire length of the gun, including through the 'cylinder'. The '.12 caliber balls' were pieces of birdshot. Dunno now what size, this was around 50 years ago. Cap and ball my eye. Yes, you stuck a Greenie Stik-M-Cap under the hammer so that when the hammer fell it fired the cap, which provided just enough energy for the 'ball' to leave the barrel.
No, I do not still have that piece of junk.
P.S. I hope nobody is dumb enough to pay $75 for that piece of junk.