Sieger is correct about the truncated cone design.
It was introduced during the initial trial periods around 1900 - 1904 in order to improve stopping power over the ogival design. The German army switched to the ogival design in 1917 when the newly introduced MP18 showed loading/feeding difficulties when used with the truncated cone design.
These are both 1917 P08 rounds:
Other armies stuck to the truncated cone design, including the Dutch KNIL who used the design until well in the second world war. They even bought truncated cone Winchester rounds.
(image by Lewis Curtis)