Pictured below is my first WW1 German exerciserpatrone, courtesy of Gary Muckel at the KCCA show last month.
This type was adopted by Germany in 1916 and consists of a steel cartridge case into which a hollow steel bullet jacket is soldered and the cartridge is copper-washed The case and bullet each have 6 longitudinally flutes to assist in identifying it as a dummy round.
Below is a scan of a page from Frank Wheeler’s cartridge column in Gun Report (April, 1966) with an interesting set of detailed drawings showing some of the dummy cartridges in the progression of 7.9 exerciserpatrone development through time, drawings by CharlesNe:
Cartridge shown in drawing #3 was made by H. Huck, Nurnberg (1916) and is the earliest form of the all steel dummy cartridge which was soon replaced by the cartridge shown in drawing #4 (information from Von der Patrone 88 zur Patrone S, Windisch, Kellner, Micke & Platzer; 2008).
Any additions, corrections, comments are most welcomed,