Hi Raimey, a short question stirred up a wasp's nest of research and answers! Your thinking is a little bit too simplicistic, but I will try to answer. First, I got a lot of information from an article by D.ZIESING in the DWJ and from contemporary books by ZIMMER (1869), KOCH (1891) and CORNELI (1884).
C.L. Berger (1794-1871) pioneered the making of cast small arms barrel steel, Krupp in Essen at that time concentrating on big guns, artillery. In 1854 Berger founded his Gusstahlwerk in Witten on Ruhr, soon aided by his sons Louis and Carl junior. Berger's Wittener steel in short order became standard on the Prussian army Dreyse needle fire rifles, but he did not only supply his steel to Dreyse's factory, but also to the German state arsenals. During the 1860s to 70s he exported vast amounts of his barrel steel to America, among this special order bar stock of 44mm diameter. His customer in the USA: Colt in Hartford, Conn.! So the barrel and cylinder of your "All American" Colt Peacemaker is made of Wittener Stahl! But "Carl Berger & Comp., Gusstahlwerk und Waffenfabrik" also established it's own gunmaking department. Two years after the death of the founder, in 1873, the company went out of control of the family. In 1882 the gunmaking branch was closed and the Wittener steelworks concentrated on supplying raw material to the guntrade, soon under competition from Krupp, who only then got interested in the small arms market.
According to Corneli the Bergers invented not only their improved coil spring striker lockwork, but also the familiar "Teschner-Collath" slide-and-tilt breech action! Teschner merely improved it by substituting conventional "Blitz" trigger plate locks, as many people then mistrusted coil-spring powered strikers on hunting guns. But Berger's striker locks can not have been entirely unpopular, as they were later used by other makers on centerfires like this double rifle, called Prince Pless guns. I have seen them combined not only with the original slide-and-tilt action, but also with the common Lefaucheux double bite break open and the original underlever Roux, known as the "Schneider-Daw" in Britain by Crudgington-Baker.
Both Berger and Teschner used combustible paper needle fire cartridges without an obturating base wad, but unlike N.v.Dreyse, who mounted the primer on the rear of the wad, placed it on a cardboard holder at the base of the cartridge, so shortening the fragile needle considerably. But at that time the ballistic virtues of "fore" or "aft" priming were much discussed. It was accepted then that firing the powder charge from the front end led to more complete combustion and increased velocity. Reminds me of Elmer Keith, who took great pains to keep the virtues of his "duplex loads", lighted from the front of the charge, secret from the Germans. Only after the first metal based cardboard true centerfire cartidges appeared, Collath as the successor of Teschner introduced his own design of needlefire cartridges. These had the obturating base wad and rimmed metal base of the centerfire, but the tube was still thought to be combustible and was made of rather thin paper. Collath's firing needle now was part of the cartridge, sort of short nail driven into the primer by the striker. Though these cartridges look much like ordinary centerfires, they are not interchangeable, as the hulls are much thinner, but the guns may be rechambered to use shotgun cartridges as we know them today. At those times, before the advent of the drawn brass centerfire case, Germans used "bore" rifles of 24 to 16 gauge with shortened shotgun cases for their hunting. Zimmer dismissed the use of those new-fangled military small-bore cartridges of about 11mm or.450 as completely unsporting!
The later Teschner-Collath or TESCO rifle cartridges are conventional brass cased centerfires, some of them only proprietary loadings of familiar numbers.