I remember the tingle. It was a target range gun, not really made for carrying around hence no ram rod thimbles. As I recall, they were built on revolver frames with that heavy breech block and the barrel, as I recall, slide in and out of the breech block. An italian company, Palmetto made some knock off in the late 1970's. I have two of the Italian made ones. One is a tight 44 (43?) caliber and the other is a tight 36 (35) caliber. They are very accurate. and were made for target shooting. They use a revolver hammer that falls againt a perc nipple that is screwed directly into the barrel breech and in line with the barrel. On the Italian makes I have, they have a simple take down screw. Take out the screw and the barrel slips right out of the breech block. Similar to some of the old stevens and rolling block take downs
Back in the late 1960's there were many experimental designs of target muzzleloaders. Tingle was one, the underhammer pistol, even a modern gun with a left handed lock mounted backwards on the right side. The sillohuette looked a bit like a Govt 45 auto. but with a flint hammer and frizzen sticking up. The advantage was that the grip could be moved forward under the barrel and gave better balance. I belonged to a club that permitted all kinds of "space guns", sort of anything goes as long as they load from the muzzle.