This is a collection of German rifle and pistol exercise and tool cartidges.  Tool cartidges are very well made, typically nickel plated and were used by technicians to test the functionality of a firearm.  The exercise cartidges are typically brass or plastic and used for training.  The plastic bodied examples will have a steel head. Certainly, a tool cartidge could also be used as an exercise round but the reverse isn't so likely.

Below, upper left; 8mm nickel plated.  Upper right; 8mm plastic.  Lower left; 8mm brass.  Middle bottom; 7.65mm nickel plated.  Lower left; 9mm plastic and nickel.

Head stamp on the nickel bodied 9mm round.

Head stamp on the plastic 9mm round.

Head stamps on the nickel bodied 8mm rifle rounds.  These were made for the Reichs Luftwaffe Mininstry and all dated 1939,

Head stamps on the 8mm nickel and brass bodied rounds.  Some are marked "Heer" or army.  The "WH" on the 3rd from the right indicates Heer, also.

Head stamps on the 8mm plastic bodied rounds made for the Heer and dated from 1941 to 1942.

Head stamps on 7.65mm nickel bodied rounds.