|This article is a stub. It is short and in need of expansion. Why not help out?|
The Steyr-Solothurn S1-100 was a Swiss-Austrian submachine gun that produced between 1929 and 1940. Originally conceived at the German Rheinmetall plant, the S1-100 was produced in Switzerland and Austria under the Steyr-Solothurn outlet. It was adopted by the Austrian Army as the MP 34 in 1934, and was sold to various other countries such as Bolivia, Portugal, China, and Japan, in a variety of different calibers.
The S1-100 was expensive to produce, but was noted for its exceptional quality. It came into limited use by the Waffen-SS during World War II, and was designated the MP34(ö) in German service. The gun was never officially adopted by the Wehrmacht. By 1940, it was largely superseded by cheaper submachine guns such as the MP40, and thus production ceased. 
— In-game description
The MP34 is better suited than most in its weapon category for longer distance firefights, and is distinct amongst SMGs for benefiting greatly from stationary, aimed fire. Its lowest rate of fire in its class at 514 RPM and low per-shot recoil both assist in consistently hitting targets at medium range, as does its damage model that is initially identical to the generic SMG damage curve but with slightly lower damage drop-off past 50m resulting in marginally higher minimum damage. However, in spite of having the highest unmodified muzzle velocity in class at 495 m/s this is still quite low relative to other medium range weapon classes, potentially complicating engagements at distance. These characteristics also means the weapon is generally worse at close range than other SMGs because of its longer time-to-kill. Also unimpressive is the 20 round magazine when stock.
Specializations for the MP34 can be applied to further add to its strength at long range, or partially remedy its weaknesses at close range. On the right path, High Velocity Bullets at Rank 1 can improve performance at extended ranges by amplifying muzzle velocity to 560 m/s, which is complemented further by the accuracy boosting Ported Barrel and Barrel Bedding upgrades at Ranks 2 and 4, the former reducing horizontal recoil to 0.085. Extended Magazine brings its capacity to the SMG standard of 32 rounds at Rank 3. The left path offers better responsiveness and minimal possible muzzle climb with Quick Aim and Enhanced Grips, while Light Bolt at Rank 3 pushes fire rate up to a more respectable 599 RPM. The Rank 4 upgrade of Bayonet is unique amongst SMGs, and could theoretically serve as a last-ditch defensive measure if caught empty.