The General Liu rifle (named for its designer – it never received an official designation that we know of) was China’s closest approach to an indigenous self-loading infantry rifle before World War II. Mechanically it used the same principles as the Danish Bang rifle – a muzzle cup captured some of the gases from firing and was pulled forward, moving a cam and lever that cycled the bolt. Liu was appointed head of the Hanyang Arsenal, and used the opportunity to put a new semiautomatic rifle into production.
The Pratt & Whitney company of Hartford was contracted to supply the machinery to mass-produce the rifle, and about a dozen sample rifles were built by P&W. They were tested in China and met with general approval, and the machinery was loaded up and shipped to Shanghai. Unfortunately, General Liu suffered a stroke and either died or was incapacitated (sources differ on this) before the tooling arrived, and it ended up sitting on the docks for years, as the rifle project foundered and never cam to fruition without Liu’s supervision. The tools were eventually sent to an arsenal and repurposed for producing other guns.
Gas-Trap M1 Garand: https://www.full30.com/video/12a744cf24ba9b3a52d0e94b95f95459
Gewehr 41(Mauser): https://www.full30.com/video/75f8e871d58e834606129e43c02d78eb
Pedersen GX & GY: https://www.full30.com/video/fdb64034a09ec798b80ce62e559fe60d