The German military establishment during WWII has a reputation for innovation and excellence, which is pretty well deserved. But even they produced some real goose eggs, and the Gewehr 41 is one of them. That the G41 was even remotely successful is a tribute to the creativity of the Walther and Mauser engineering staffs, as the gun was fatally flawed from the start by the conditions put on the design. Primarily at fault was the military insistence that the barrel not have a gas port drilled in it. I'm sure there was some theoretical rationale for this requirement, but it was not a reasonable one. Some of the other restrictions were similarly silly, like the requirement that the gun must be able to operate like a bolt action using the same manual of arms as the K98k, and that there be no moving parts on the top surface of the gun (it is revealing that both Walther and Mauser flat out ignored one or more of these written requirements, despite being German companies). The root of the G41 procurement conditions can only really be a suspicious distrust of self-loading rifles that cropped up in many pre-WWII ordnance departments worldwide. It's the same stubborn lack of foresight that produced repeating rifles with magazine cutoffs.

Anyway, Walther and Mauser both provided sample designs for the G41, and after trialing both, the Walther design was accepted for mass production (the Mauser design was rather more complex and intricate). The designs flaws were quickly realized, and production moved to the G43, which used essentially the same receiver but with a standard gas port system.