I definitely understand why the gun was not adopted by any major military if any at all to my knowledge. But was it actually a reliable gun? Judging by the direct feed angle, it stands to reason that it would actually be quite reliable. What was probably holding it back in my book is appalling ergonomics, price, complexity, and high recoil. I know next to nothing about the Borchardt though. And my understanding of mechanics and engineering is definitely not expert.