In the years following world war 1, the Soviet Union like many other countries realized it was extraordinarily important to develop a man-portable light machine gun that could be operated and carried by only one soldier.
Out of the development program, the Soviet Union developed the DP-28 (And prototype dp-26) series machine gun. For its time, it was very advanced, featuring a relatively light (25lbs / 11.5kg) package.
The DP-28 was the primary light machine gun available to the Soviet Union during the Winter War against Finland as well as for most of WW2. One of the most useful features of this machine gun was the large 47 round magazine. While inferior to the belt-fed system of the German MG34 and MG42, it had a much higher capacity than the 30 round capacity of the British Bren Gun and the 20 round capacity of the American BAR.
While the DP-28 was a extraordinarily useful gun, by 1944 the Soviet Union realized there were some major shortcomings. The DPM was manufactured to address these concerns. During the development of the gun, there were a few goals.
- Develop a more robust bipod
- Improve the recoil/gas system and make it adjustable for adverse conditions
- Allow crews to disassemble the gun without removing the butt stock
- Add a pistol-style grip to aid in function.
These issues were quickly addressed with the DPM series and production was started in 1944. While many parts are compatible with the DPM and DP-28, some are not, primarily part of the gas system and many of the dis assembly parts as well. Unlike the DP28 series, the DPM can be easily broken down without the aid of tools and serviced. One severe problem with the DP-28 series was that when the user removed the butt stock, the bolt recoil spring had a tenancy to launch from the gun under tension and become lost. This was a major concern when there were so few spare parts available. Due to the protruding recoil assembly, the bolt has more room to recoil and is under less pressure ,aiding ease of dissassembly.
Additionally, gas regulation on the DPM is superior to that of the earlier models. The recoil system can be adjusted to deal with matter buildup on parts (Due to lack of cleaning) as well as low-powered ammunition. This made the DPM much more useful in poor conditions.
After WW2, the DPM was once updated again, forming the RP-46 which added a belt-feed system. This system allowed users to fire without the need to reload the platter-style magazine on the gun.
Further after the war, tooling was sold or given to many client states such as Poland and China. China then produced the Type 58 machine gun, which was a direct copy of the Soviet DPM.