The Ruchnoy Pulemyot Degtyaryova Pekhotny (Degtyaryov hand-held infantry machine gun) or DP was a light machine gun used by the Soviet Union starting in 1928. It fired the 7.62x54mmR cartridge and was cheap and easy to manufacture - early models had fewer than 80 parts and could be built by unskilled labour. The DP was especially able to withstand dirt. In tests it was buried in sand and mud and was still capable of firing more than 500 rounds. The DP's main drawback was its bipod; this part could not withstand much abuse and broke easily. Also, the magazine, which was usually a pan with 47 rounds that fed in from the top, was relatively small and continuous fire for long periods could not be relied on as much as contemporary belt fed weapons. It took some time to load a new magazine onto the weapon, and each magazine took a much longer time to load with ammunition. However, the DP's lower cyclic rate of fire meant a reduced risk of the barrel overheating. The DP machine gun was supplemented in the 1950s by the more modern but problematic RPD machine gun and entirely replaced in Soviet service by the general purpose PK machine gun in the 1960s.