Staff Writer (Updated: 10/9/2016):
Externally, the DP was of a decidedly Russian design, characterized mostly by the use of its pan magazine atop the forward portion of the receiver. The receiver itself was rounded at the edges with slab sides and the forend was metal with oblong, rectangular venting for cooling the barrel. A bipod was affixed to the forward portion of the barrel jacket to which the barrel protruded a distance away from the gun body. The muzzle was capped by a conical flash suppressor. The trigger unit was held under the aft portion of the receiver and protected by an oblong trigger ring. There was no pistol grip but instead an ergonomic shoulder stock. A shoulder strap could be linked to the left side of the weapon, this at the stock and at the vented forend barrel jacket. Sights were present at the receiver rear top (tangent leaf) and at the end of the barrel jacket (front post with ears). The weapon system weighed in at approximately 20.11lbs.
The DP was chambered to fire the Russian 7.62x54mmR cartridge, this from a 47-round pan magazine. Other versions eventually came online that featured belt-feeding and a 30-round overhead box magazine instead. The weapon was a gas-operated system achieving a rate-of-fire of 500 to 600 rounds per minute. Muzzle velocity was listed at 2,755 feet per second. Effective range was out to 800 meters. The barrel measured in at 23.80 inches with a 4-groove, right-hand twist design. The DP utilized a simple locking mechanism that made for a solid and robust machine gun. The internal working components were well protected from dirt and dust that would be encountered on most any battlefield. A piston tube was mounted underneath the barrel assembly and contained the operating spring. Construction was rather solid by Soviet standards.
However, the DP was not without any weaknesses. She was designed to only fire in full-automatic mode. The placement of the operating spring under the barrel meant that it was susceptible to the heat generated by constant firing and could become warped. As a cooling feature for the receiver, the bolt would stay open between pulls of the trigger which could invite foreign objects into the mix. The use of the long rimmed Russian 7.62mm cartridge also led to more jamming of the feed that was desired. The 47-round pan magazine also limited suppressive fire to an extent, less functional than a traditional belt-fed system at least. Magazine loading and reloading was a chore. The bipod was rather fragile as well and prone to breaking in the heat of battle. Regardless, the type was one of the finest of its kind before, during and after the war, seeing use in other distinct forms based on the original and seeing use across the globe by Soviet-allied or friendly nations. Its ease of manufacture ensured it would be a world mainstay.
The DP LMG was advanced into other versions beyond the original. The PPD-36 was a magazine-fed model with a 30-round magazine. The DPM became a "modernized" form that appeared between 1943 and 1944 and proved a mainstay in the Red Army by 1945, differentiated by its reworked bipod and addition of a pistol grip to compensate for the recoil spring tube extending out of the rear of the receiver. The DPM was locally-produced in China as the Type 53. The DA was an aircraft mounted model while the DT and DTM (modernized) variants were vehicle mounted types. The DTM-4 fitted four machine guns in a quad-mounting for anti-aircraft work. The RP-46 was a belt-fed model that appeared in 1946. China produced these locally under the designation of "Type 58".
Some 795,000 DP LMGs were produced in all. The type went on to serve more than just the Red Army and included the armies of Cambodia, China, North Korea, North Vietnam and Vietnam. The Finns made use of the DP LMG as captured examples (nicknaming them as "Emma") during their struggle with the Red Army in the Winter War of World War 2. It bears mention that nearly all of the above operators made use of the RP-46 belt-fed variant.
In the Soviet Army, the DP LMG was formally replaced in frontline service by the more modern PK machine gun series late in the 1960s.