I am only an collector. Soldering the rings was usual in germany since the beginning of 1900. It was one of the big problem - the scope had to be dissasembeld for soldering. The two piece rings was not used often in germany before 1945.
The pics shows about 40% of my collection, so there is only one alloy with rail on the last pic- the one in the middle of the first row. With these the problems of using rings were away, first offered around 1928.