In fact Schmeisser's Haenel 28R was the first repeating spring air pistol to be introduced, around 1928. Although repeating air rifles were well known by then, there did not seem to have been much appetite for developing corresponding pistols, and it was Schmeisser who first realised that this was a niche market he could tap into. I don't know of any earlier air rifles using his rising block / concentric magazine concept, so why he did not patent the design is a mystery.