How was the K31 improved?
The action was almost completely re-done. In fact technically, the K31 is not a Schmidt-Rubin, although it is still a straight-pull. The K31 action was shortened and the locking lugs were moved to the front of the bolt. This created a stronger action, and allowed the length of the K31 to be the same length as the 1911 carbine, yet still have a 2″ longer barrel. The K31 was adopted in 1933 and stayed in service until 1958.
