Complex sentence: The Manchurian Mauser Rifle was a rifle that implemented characteristics of both the Mauser Model 1898 and the Arisaka rifles, that was built entirely in the Mukden arsenal in Manchukuo.
Split into simpler sentences: The Manchurian Mauser Rifle was a rifle that implemented characteristics of both the Mauser Model 1898 and the Arisaka rifles. It was built entirely in the Mukden arsenal in Manchukuo.