Type B weapons are firearms designed to be extremely cheap to produce, with the intent of arming militias and guerilla fighters anywhere in the world. The concept started with the last resort weapons during the last days of the War of the Dawn. This concept was picked up by Mitannia after the revolution and expanded upon.
Though Mitannia does not arm its standing army with these weapons, a large stockpile of them are kept for conscripts. They are also regularly sent towards other humans in need of arms, most notably Turangar, Elruth-Mareca, and the Voskgardian National Reclamation Army.
Though they are often uncomfortable to fire and unpopular with troops compared to the well crafted, wooden stocked standard issue rifles, no one doubts their necessity in a world where humanity is backed in a corner. Most Type B weapons lack the wooden stocks used in regular rifles and instead use a metal frame.
This causes them to be more uncomfortable to fire. But to many parts of humanity, a gun like this is better than no gun.