Comparing: Pz.Sfl. IVb vs. Birch Gun

SPG prototype equipped with a 105-mm howitzer. Developed in 1939 by the Krupp company, a total of 8 prototypes were manufactured and sent to the Eastern Front for trials. However, the SPG never entered mass production.

In the 1920s, British engineers explored the idea of an SPG on a tank chassis. Development of the vehicle started in 1923 at the Royal Arsenal, Woolwich. It was based on the Vickers Medium Mark II, the chassis of which could carry the required modules. A total of seven prototypes were manufactured and joined the Experimental Mechanised Force established on May 1, 1927. Later, the unit was disbanded, along with the SPG program.