The annals of small arms designs are filled with near perfect, odd and/or unsuccessful weapons. The Czech tradition of innovative small arms designs began in the early 20th century and continues to this day. In the 1920s, however, there was a semi-automatic rifle that should have received more attention, the ZH-29.
A well-made rifle, the ZH-29 came with a 10 or 20-round detachable magazine. While this is common for modern weapons, by 1929 it was still fairly rare, outside say a handful of larger automatic rifles like the BAR. The detachable magazine wasn't always meant to come out. In combat, the ZH-29 was designed to be reloaded by stripper clips.
Now you're wondering about the title of the article, angled barrel? Yes, when the designers of the ZH-29 brainstormed, they came up with the concept of a side locking/angled barreled rifle.The barrel of the rifle is not centered on the rifle. Looking at it with the fore-stock removed one can see a slight right, off-center orientation. The reason for this was the unusual decision to have the gas operated bolt lock on the left side of the receiver. This meant that the entire right side of the receiver was open and expose over half of the bolt group. While easily prone to fouling, this also meant it was much easier to clean.
When rounds were expended, the magazine could be removed with the bolt remaining to the rear. However, to return the bolt to battery one didn't need to hit a separate bolt release or work the bolt spur. No, the operator pulled the trigger which sent the bolt forward, a very unusual way to release a bolt. And when a new magazine was inserted, the bolt group's reward travel cocked the internal hammer which then could be released by the pull of a trigger. Unusual because it could easily invite operator error that could lead to dangerous negligent discharge.
Chambered in 7.92mm, the ZH-29 never saw widespread European service, but did see contracts for use in China and Ethiopia. Also, the design saw a brief stint in the United States re-chambered for consideration as a new combat rifle.