<P> Once the manufacturing difficulties of non milled receivers had been overcome, a redesigned version designated the AKM (M for "modernized" or "upgraded"; in Russian: Автомат Калашникова Модернизированный (Avtomat Kalashnikova Modernizirovanniy)) was introduced in 1959 . This new model used a stamped sheet metal receiver and featured a slanted muzzle brake on the end of the barrel to compensate for muzzle rise under recoil . In addition, a hammer retarder was added to prevent the weapon from firing out of battery (without the bolt being fully closed), during rapid or fully automatic fire . This is also sometimes referred to as a "cyclic rate reducer", or simply "rate reducer", as it also has the effect of reducing the number of rounds fired per minute during fully automatic fire . It was also roughly one - third lighter than the previous model . </P> <Table> <Tr> <Th> Receiver type </Th> <Th> Description </Th> </Tr> <Tr> <Th> Type 1A / B </Th> <Td> The original stamped receiver for the AK - 47 first adopted and produced in 1949 . The 1B was modified for an underfolding stock with a large hole present on each side to accommodate the hardware for the underfolding stock . </Td> </Tr> <Tr> <Th> Type 2A / B </Th> <Td> The first milled receiver made from steel forging . It went into production in 1951 and production ended between 1953 and 1954 . The Type 2A has a distinctive socketed metal "boot" connecting the butt stock to the receiver and the milled lightening cut on the sides runs parallel to the barrel . </Td> </Tr> <Tr> <Th> Type 3A / B </Th> <Td> "Final" version of the AK - 47 milled receiver made from steel bar stock . It went into production between 1953 and 1954 . The most ubiquitous example of the milled - receiver AK - 47 . The milled lightening cut on the sides is slanted to the barrel axis . </Td> </Tr> <Tr> <Th> Type 4A / B </Th> <Td> AKM receiver stamped from a smooth 1.0 mm (0.04 in) sheet of steel supported extensively by pins and rivets . It went into production in 1959 . Overall, the most - used design in the construction of the AK - series rifles . </Td> </Tr> </Table> <Tr> <Th> Receiver type </Th> <Th> Description </Th> </Tr> <Tr> <Th> Type 1A / B </Th> <Td> The original stamped receiver for the AK - 47 first adopted and produced in 1949 . The 1B was modified for an underfolding stock with a large hole present on each side to accommodate the hardware for the underfolding stock . </Td> </Tr>

How much damage can a ak 47 do