StG 45M

The StG 45(M), or MP 45(M), was a prototype assault rifle developed by Mauser for the German Wehrmacht during WWII. It featured a roller-delayed blowback mechanism and fired the 7.92×33mm Kurz cartridge at approximately 450 rounds per minute.

Development began with the MKb Gerät 06, which faced issues like bolt-bounce. Karl Maier addressed these by adjusting receiver angles and introducing fluted chambers to prevent case separation. The rifle incorporated a straight-line recoil system, enhancing controllability, similar to earlier designs like the FG 42 and StG 44.

Intended as a cost-effective replacement for the StG 44, the StG 45(M) was produced in limited numbers—only about 30 units before WWII ended. Post-war, German engineers continued developing this design in France, leading to various prototypes and influencing future arms like the Heckler & Koch G3 and MP5. Other notable weapons using similar systems include the SIG SG 510.